Ap world unit 7 vocab

AP EXAM REVIEW!

Conscription

The mandatory enlistment of citizens (typically males) into national military service, widely used by states to rapidly expand armies during times of war or national emergency

Stalemate

A deadlock in a conflict where neither side can achieve a decisive victory or make significant territorial progress, often leading to a long, exhausting war of attrition

• a situation where neither side can gain an advantage or make progress ; endured throughout WWI

Propoganda

Information, especially of a biased or misleading nature, used to promote or publicize a particular political cause or point of view.

• a systematic effort to influence public opinion by spreading inaccurate or biased information

Reparations

Payment for war damages; compensation imposed on a nation for the damages and losses incurred during a conflict, often involving monetary payments or the return of property.

Lusitania

A British passenger ship that was sunk by a German U-Boat on May 7, 1915. 128 Americans died; one of the reasons why the U.S. entered WWI

Zimmermann Telegram

A secret diplomatic German message to Mexico supporting the Mexican Government in regaining Arizona and Texas if the Mexicans declared war on the United States, a factor propelling the U.S into World War I

• (January 1917) a secret diplomatic communication from Germany to Mexico, offering to reclaim territory lost to the U.S. in 1848 if Mexico allied with Germany; it became the final reason that caused the U.S. to join WWI

Total war

The complete mobilization of a nation's resources, both military and civilian, to achieve victory in conflict

• A conflict that involved not only the military but their nation's domestic resources, like civilian infrastructure and manufacturing

ANZAC

The Australian and New Zealand Army Corps was formed in 1914. It was a combined force of volunteer soldiers from Australia and New Zealand that served under the British Empire during World War I.

• (1914-1916) the Australian and New Zealand Army Corps; it was a WWI unit of Austrailan and New Zealand soldiers fighting for the British Empire, operating on colonial territories

Gallipoli

A failed Allied military operation during World War I, targeting the Ottoman-controlled Gallipoli Peninsula to secure the Dardanelles Strait, knock the Ottoman Empire out of the war, and supply Russia; a peninsula in northwestern Turkey

• (1915-1916) a year-long British campaign over the northwestern Turkish peninsula aimed at capturing Constantinople and securing a sea route to Russia; it failed and left more than 500,000 casualties

Big Four (Paris Peace Conference)

Woodrow Wilson (United States), David Lloyd George (Great Britain), Georges Clemenceau (France), and Vittorio Orlando (Italy); the leaders of the victorious Allied powers, who played a crucial role in negotiating the Treaty of Versailles in 1919

Fourteen Points

A set of principles proposed by U.S. President Woodrow Wilson in 1918 aimed at achieving lasting peace after World War I. These points emphasized self-determination for nations, free trade, disarmament, and the establishment of a League of Nations

League of Nations

A world organization established in 1920 to promote international cooperation and peace. It was first proposed in 1918 by President Woodrow Wilson in his Fourteen Points, although the United States never joined the League. Essentially powerless, it was officially dissolved in 1946.

Treaty of Versailles

The peace treaty signed in 1919 that officially ended World War I, imposing heavy reparations and territorial losses on Germany; set the stage for WWII

Weimar Republic

The German republic founded after the WWI and the downfall of the German Empire's monarchy; Germany's government from 1919 to 1933, the period after World War I until the rise of Nazi Germany

• a democratic government established in Germany after WWI up until the Nazi's rule, faced great instability from WWI reparations and resentment from those against the Treaty of Versailles

Trench warfare

A form of warfare in which opposing armies fight each other from trenches dug in the battlefield; used prolifically during WWI. Many soldiers died from diseases caused by unhygienic conditions

• A form of warfare in which armies stayed and fought in long ditches as defense, conditions were often unsanitary and dangerous

Poison gas/machine guns

Revolutionary, mechanized technologies defining trench warfare. They made war impersonal and incredibly lethal, creating long-term stalemates. Machine guns fired approximately 500 rounds per minute, while poison gas caused mass casualties (blindness, choking).

Submarines (U-boats)

German military submarines used in WWI and WWII, representing a major technological shift in naval warfare; ships that traveled underwater

airplanes/tanks

Pivotal technological innovations that revolutionized warfare, breaking the stalemate of trench warfare during WWI and enabling rapid, mechanized movement in WWII. Both were equipped with weapons

All Quiet on the Western Front

(1929) a novel written by Erich Maria Remarque about a group of German soldiers in WWI that served as an anti-war statement by providing a vivid depiction of the harsh realities of trench warfare

Deficit spending

A situation in which a government spends more money than it takes in to stimulate economic activity

Relief, Recovery, Reform

The primary pillars of Franklin D. Roosevelt's New Deal, designed to address the Great Depression

• the three goals of FDR's New Deal: relief for citizens who were suffering, recovery to bring the nation out of the Depression, and reform to change government policies to prevent similar economic disasters

Kolkhoz

A form of collective farm in the Soviet Union where farmers pooled land, labor, and equipment to work together under state-mandated production quotas

• collective farms in the Soviet Union where many farmers worked together on shared land

Great Depression

(1929-late 1930s) a worldwide economic crisis caused by agricultural overproduction and the U.S. stock market crash; it resulted in massive unemployment, declines in spending and foreign trade, and increased poverty

New Deal

A series of programs and policies implemented by President Franklin D. Roosevelt in the United States during the 1930s aimed at providing relief, recovery, and reform in response to the Great Depression.

• a group of policies and programs created under President Franklin Delano Roosevelt, which used Keynesian economic principles

New Economic Plan (NEP)

A 1921 initiative by Vladimir Lenin to revive the Soviet economy after the Russian Civil War by introducing temporary, limited capitalism; a temporary retreat from Communist economic policies instituted by Lenin; reintroduced private trade

• (1921-1929) a temporary economic reform established by Vladimir Lenin that reintroduced private trade on a small scale while under the Soviet state-controlled economic framework, had success but ended shortly after Lenin's death

Five-Year Plan

State-directed, centralized economic initiatives, pioneered by Joseph Stalin in the Soviet Union (beginning 1928), designed to rapidly transform agrarian nations into industrial, socialist powers and collectivize agriculture; meant to transform the Soviet Union into an industrial power

• A series of economic goals by Joseph Stalin of the Soviet Union that heavily emphasized the transformation of an agricultural nation to an industrial powerhouse

Russian Civil War (1918-1921)

(1917-1922) A multi-party war in the Russian Empire resulted from the Bolsheviks' seizure of power; it included the Red Army (military force of Bolsheviks to defend the Communist Party) against the White Army (which consisted of monarchists, liberals, and anti-Bolshevik socialists)

Spanish Civil War (1936-1939)

A brutal conflict between the left-wing Republicans (Loyalists) and the right-wing Nationalists, led by General Francisco Franco. Regarded as a "dress rehearsal" for World War II, it pitted fascism against democracy and communism, with international involvement aiding Nationalist victory

• (1936-1939) a brutal conflict fought in Spain between the Republicans (Popular Front) and Nationalists (right-wing groups) led by Francisco Franco

Guernica

A town in northern Spain's Basque region that became internationally known after the bombing by Nazi German forces during the Spanish Civil War on April 26, 1937. This tragic event inspired Pablo Picasso to create one of his most famous paintings, which serves as a powerful anti-war symbol

• a Spanish town in northern Spain's Basque region that was brutally bombed by the Germans and Italians aiding the Nationalists in the Spanish Civil War; the tragedy was immortalized in a painting by Pablo Picasso

Politburo

The executive committee and the principal policymaking body of the Communist Party of the Soviet Union

• the executive committee and leading policy-making body of the Communist Party of the Soviet Union ; Joseph Stalin took control of the organization, making him dictator

Fascism

A far-right political ideology that emphasized extreme nationalism, suppression of political opponents, centralized economic control, and justification of violence to achieve goals

Totalitarian State

A political system where a single-party government, often led by a dictator, seeks total control over all aspects of society

• a political system where a single party has absolute control over all aspects of society

Luftwaffe

The aerial warfare branch of the German Wehrmacht during World War II, responsible for air defense and offensive operations; the German air force before and during World War II

• Nazi Germany's air force

Union of Soviet Socialist Republics (USSR)

Russian federal system, controlled by the Communist Party established in 1923; a socialist, transcontinental state spanning Eastern Europe and Northern Asia, serving as the world's first communist country.

• (1922-1991) a socialist state located in Eurasia that emerged from the Russian Revolution of 1917; it's known for its radical changes to its economic, society, and politics including industrialization and collectivization of agriculture (kolkhoz)

Basque Region

An autonomous, culturally distinct territory spanning northern Spain and southwestern France; contains Guernica

• a region in northern Spain that has an autonomous community residing within, includes the town of Guernica

Gulag

A system of forced labor camps in the Soviet Union during the Stalin era, in which millions of criminals and political prisoners were held under harsh conditions and brutal treatment

• Soviet Union labor camps where many political opponents were sent, leaving more than a million deaths

PEMEX

Mexico's state-owned oil company, created in 1938 by President Lazaro Cardenas following the nationalization of the foreign-owned oil industry

• aka Petróleos Mexicanos, a Mexican state-owned company that managed petroleum products and had nationalized Mexico's oil industry

Decolonization

The process through which colonies gain independence from colonial powers, leading to the establishment of sovereign nations; this movement accelerated after WWII

Balfour Declaration

A British statement during WWI that stated that European Jews should have a national home in Palestine

Civil Disobedience

The active, nonviolent refusal to obey certain laws or governmental demands as a form of protest; citizens disobey their government by breaking an unjust law in order to bring about social or political change

• a form of political participation that reflects a conscious decision to break a law believed to be immoral and to suffer the consequences

Pan-Arabism

A 20th-century political and cultural ideology advocating for the unity and solidarity of Arab nations across North Africa and the Middle East, rooted in shared language, culture, and history

• a nationalist movement that called for the unification of all lands in Middle East and North Africa, rose following Arab infuriation over the League of Nations mandates

Indian National Congress

A political party in India formed in the late 19th century to air grievances against the colonial government. By the end of WWI, it had become a strong voice for independence

Satyagraha movement (devotion to truth)

A form of nonviolent resistance developed by Mohandas Gandhi, where Indians perform civil disobedience to expose the injustices of the British colonial government and advocate for change

• A philosophy and method of nonviolent resistance developed by Mahatma Gandhi. It combines satya (truth) and agraha (firmness) to encourage civil disobedience and peaceful protest to challenge injustice and colonial oppression while maintaining respect for the oppressor

Salt March

Gandhi's campaign that protested against the British ban over Indian production of salt because of British's desire of a salt monopoly; thousands of Indians went to the Arabian Sea to pick up a few grains of salt in protest

Chinese Communist Party (CCP)

Political party of the People's Republic of China had been led by Mao Zedong, who advocated for a socialist society under Marxist-Leninist principles and believed a Chinese revolution could work by peasant revolts

Kuomintang

The Chinese Nationalist Party, formed by Sun Yat-Sen who advocated for full independence and industrialization; the party's successing leader, Chiang Kai-shek, was conservative and distrusted communism, which even led to him initiating the Chinese Civil War against Mao's forces

Manchukuo

A puppet state established by Imperial Japan in Northeast China (Manchuria) after the 1931 invasion

• a Japanese puppet state established in 1932 in Manchuria (formerly part of China but invaded by Japan) as a means of imperial expansion and resource exploitation; Puyi, the last Qing emperor was placed as head of state to make it seem like an independent Chinese state

Greater East Asia Co-Prosperity Sphere

An imperial concept led by Japan to create a self-sufficient bloc of Asian nations (in East and Southeast Asia) free from Western colonial influence, while promoting mutual benefit and cooperation; Japan used this to justify expansion, replacing European control with its own hegemony.

• a Japanese concept that claimed Japan created a bloc of Asian nations (Phillippines, Dutch East Indies, British Malaya, Burma, and numerous Pacific islands) to free them from Western imperialism

March First Movement

a Korean non-violent protest against the Japanese; the Japanese forces cracked down on them which left thousands of Koreans killed, but it demonstrated Korean nationalism

Long March

the year-long, 6,000 mile retreat of Mao's forces into northern China after being attacked by Chiang Kai-shek's forces in 1934; despite being weakened, it won support of peasants for their determination which eventually aided in the success of Communist control over China

May Fourth Movement

a Chinese movement characterized by a drive in nationalism, push for modernization, and reform against foreign imperialism; it began as a protest against the Treaty of Versailles, awarding German concessions in the Shandong Province to Japan instead of returning it to China

Submarines

military watercraft capable of going underwater

U-boats

German military submarines (Unterseeboot) used during WWI to attack enemy naval vessels

Airplanes

airbone vehicles that during WWI were originally used for reconnaissance (observation) but later aerial combat with the addition of machine guns

Tanks

heavy armored vehicles that could travel across various terrain while keeping soldiers protected and firing shots at the enemy lines

Machine guns

rapid-fire, fully automatic weapons developed in the late 19th century that could fire around 500 rounds of ammunition per minute

Poison gas

a WWI chemical weapon in which certain gases like chlorine, phosphene, and mustard gas caused gradual but very painful and often chronic effects

Turkification

An effort to make all citizens of the multiethnic Ottoman Empire identify with Turkish culture, which was heavily Islamic.

• The cultural process of assimilating people, especially among the Ottoman Empire's citizens, into identifying with Turkish culture

Bolshevik

An organization representing the revolutionary working class of Russia under the leadership of Vladimir Lenin, seized power and set up a communist government with Lenin at its head in the fall of 1917.

• A group of revolutionary working-class Russian Marxists who, under the leadership of Vladimir Lenin, seized power and established a communist government

Communists

Believed that workers eventually should own the means of production and that collective ownership would lead to collective prosperity and a just society

• people who believed in collective ownership, workers owning means of production, and a classless society which combated the capitalist system

Young Turks

A reformist political group that arose in the Ottoman Empire, which advocated for modernization, secularism, nationalism, and a constitution similar to European ones

Mexican Revolution

(1910-1920) An armed rebellion in Mexico aimed at overthrowing the dictator Porfirio Diaz; it created a period of political instability and violence that caused around 2 million deaths

Institutional Revolutionary Party (PRI)

The political party established in 1929 that dominated the political landscape of Mexico; it was crucial in navigating challenges left after the Mexican Revolution, in which they promoted nationalism, economic stability, and social reform

Great War

Commonly known as World War I, it was a global conflict that lasted from 1914 to 1918, involving many of the world's great powers, divided into two main alliances: the Allies and the Central Powers.

Triple Entrente

A military alliance between Great Britain, France, and Russia; all three viewed Germany as a rival.

• A military alliance between Great Britain, France, and Russia involved in the fighting of World War I against the Central Powers; each country had shared opposition towards Germany but for different reasons

Triple Alliance

A military pact between Germany, Austria-Hungary, and Italy in the years before WWI.

• pre-WWI alliance between Germany, Austria-Hungary, and Italy; rivals of the Allies

Central Powers

(1914-1918) World War I alliance between Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria, that fought against the Allied Powers.

• A coalition of countries formerly known as the Triple Alliance and includes Germany, Austria-Hungary, the Ottoman Empire, and Bulgaria

Black Hand

A secret Serbian nationalist organization devoted to ending Austrian-Hungarian presence in the Balkans; it played a pivotal role in the eruption of WWI when one of its members, Gavrilo Princip, assassinated Archduke Franz Ferdinand of Austria-Hungary

Militarism

The belief that a country should maintain a strong military capability and be prepared to use it aggressively to defend or promote national interests

• The belief of military preparedness, establishing a strong military and using it aggressively to defend or promote nationalism

Secret Alliances

Groups whose members secretly agree to protect and help one another when attacked; confidential, pre-World War I agreements between European nations pledging mutual military support in case of attack.

Self-determination

The idea that peoples of the same ethnicity, language, culture, and political ideals should be united and should have the right to form an independent nation-state.

Sun Yat-sen

A Chinese revolutionary known as the "Father of Modern China". He was instrumental in overthrowing the Qing Dynasty during the 1911 Xinhai Revolution and served as the Republic of China's first provisional president. He founded the Kuomintang (Nationalist Party) and advocated for the "Three Principles of the People": Nationalism, Democracy, and People's Livelihood

• (1866-1925) Chinese revolutionary and political leader who played a role in overthrowing the Qing Dynasty to establish the Republic of China; he advocated for democracy, nationalism, and livelihood for the republic

Profirio Diaz

Dictator in Mexico from 1876 to 1911. Overthrown by the Mexican Revolution of 1910

Atatürk

aka Mustafa Kemal; led the Turkish National Movement who defeated British and established the Republic of Turkey in 1923, making him the founder of modern Turkey

Sudetenland

A mountainous border region of Czechoslovakia containing over 3 million ethnic Germans; Germany thought this land was rightfully theirs due to the large German-speaking population

• An area in western Czechoslovakia that Hitler wanted to claim as he believed it was a natural extension to the empire due to most of the people there speaking German

Danzig

A Polish port city that, before WWI, belonged to Germany. After WWI, when the lands near it became part of the Polish Corridor, it was declared a "free city" independent of any country. It was reincorporated into Nazi Germany in 1939.

• a northern Poland port city that Hitler wanted to claim, merely as an excuse to invade Poland

Kristallnacht

November 1938- “Night of Broken Glass”; anti-Jewish riots that started as a result of a Jewish teenager assassinating a German diplomat. It left more than 90 Jews dead, destroyed synagogues and shops, and sent more than 30,000 Jews to concentration camps

Lebensraum

Hitler's expansionist theory based on a drive to acquire "living space" for the German people; the territory that a state or nation believes is needed for its natural development, especially associated with Nazi Germany

• known as “living space” a core Nazi concept that promoted the idea that Germany needed expansion

Anschluss

With the Anschluss (political union), Austria officially became part of the Third Reich; German for "connection" or "joining", refers to the Nazi German annexation of Austria on March 12, 1938

• The political union of Germany and Austria, Austria annexed because of Hitler’s desire to bring it under German rule

Munich Agreement

Allowed Hitler to annex the Sudetenland in return for a promise that Germany would not take over any more Czech territory; a failed diplomatic pact allowing Nazi Germany to annex Czechoslovakia's Sudetenland in exchange for a pledge of peace

• agreement that Hitler annex Sudetenland in return for a promise that Germany would not take over any more Czech territory, a horrific miscalculation that led to Hitler seizing all of Czechoslovakia

Axis Powers

The coalition of nations—primarily Germany, Italy, and Japan—that fought against the Allied Powers in World War II

Nazis

The National Socialist German Workers' Party was a far-right, totalitarian political party led by Adolf Hitler that ruled Germany from 1933 to 1945; the party's ideology centered on nationalism, anti-communism, and a belief in the superiority of the Aryan race, leading to aggressive expansionist policies and mass atrocities during World War II.

• aka the National Socialist German Workers' Party, a far-right, totalitarian political group that seized control of the German government in 1933 under Adolf Hitler; they believed in the superiority of the Aryan race which was used to justify their expansionism policies

Mein Kampf (My Struggle)

A 1925 autobiographical manifesto by Adolf Hitler, written in prison, outlining his Nazi ideology; Hitler had declared his extreme anti-semitic views in this book

• an autobiographical book written by Adolf Hitler during his imprisonment where he declared his extreme anti-semitic views and ideologies that become the basis of the Nazi party

Aryans

Germanic people seen as the master race; a pseudoscientific racial ideology adopted by the Nazi party to classify people of Northern European descent as a superior "master race"

• what Nazis deemed the "master race" as they claimed they were superior above all other races; defined as people of North-Western European descent with blonde hair and blue eyes

Appeasement

A policy followed by Britain involving giving into Germany's demands to keep peace and avoid war ; a 1930s foreign policy, primarily used by Great Britain and France, aimed at avoiding war with aggressive totalitarian states (Nazi Germany and Fascist Italy) by making territorial and political concessions

• a policy of giving in to an aggressor's demands in order to avoid war; the British did this with Germany

• The Sudetenland was a mountainous, German-speaking border region of Czechoslovakia demanded by Hitler and annexed by Nazi Germany following the 1938 Munich Agreement. It was a key flashpoint in interwar European tension, symbolizing Western appeasement and the collapse of Versailles-era peace, leading to the occupation of Czechoslovakia

Eugenics

A pseudoscientific, social, and political ideology that advocates for improving the genetic quality of the human population through selective breeding, aiming to promote "desirable" traits and eliminate "undesirable" ones

• pseudo-scientific belief and practice of improving the genetic quality of the human population through selective breeding and sterilization, influenced Nazi Germany's policies on racial ideologies

Vichy

The authoritarian, pro-Nazi collaborationist government established in the unoccupied southern zone of France after its defeat by Germany in WWII; the French set up a new pro-Nazi regime based in Vichy under Marshal Henri-Philippe Petain

• a city in central France that became the center of a pro-Nazi regime set up by the French after the German invasion of France in May 1940

Lend-Lease Act

U.S. legislation allowing President FDR to sell, transfer, exchange, or lease military materials to any nation deemed "vital to the defense of the U.S.". It effectively ended U.S. neutrality, allowing aid to Britain, the USSR, and China to fight the Axis powers.

• (March 1941) law that authorized the U.S. President to lend war materials to other Allied powers like Great Britain without direct combat involvement

Destroyers for Bases Agreement

An agreement in which the US promised to deliver 50 destroyers in exchange for eight British air and naval bases in the Western hemisphere

Battle of Britain

An aerial battle fought in World War II in 1940 between the German Luftwaffe (air force), which carried out extensive bombing in Britain, and the British Royal Air Force, which offered successful resistance against Nazi invasion

• (July 1940-October 1941) a series of aerial battles between the German Luftwaffe and the British RAF over German ambitions to negotiate a peace agreement favorable to Germany, ended in Hitler forced to postpone the invasion of Britain

Siege of Leningrad

The Nazi army's unsuccessful attempt to capture the city of Leningrad in the Soviet Union during World War II (they failed largely due to the harsh Russian winter). As many as 1 million civilians perished during the siege

• (September 1941-January 1944) the Nazi's army blockade over the Soviet city of Leningrad in an attempt to capture the city; it led to the deaths of over a million civilians

Pearl Harbor

The December 7, 1941, surprise attack by the Imperial Japanese Navy on the U.S. naval base at Pearl Harbor, Hawaii, killed over 2,400 Americans, severely damaging the U.S. Pacific Fleet. This event directly caused the U.S. to enter World War II, ending its policy of neutrality.

• a U.S. naval base in Hawaii that was attacked by Japan on December 7th, 1941, believing the U.S. would negotiate a settlement favorable to Japan and their imperialistic efforts; the U.S. declared war the next day

Battle of El Alamein

A pivotal World War II confrontation in Egypt, where British forces under Montgomery defeated Germany's Rommel, marking a major turning point in the North African Campaign; World War II battle in which the Britain won a decisive victory over Germany in Egypt, securing the Suez Canal

• (October-November 1942) WWII battle in Egypt that ended in an Allied powers victory by the British over Germany, removing the Axis power's threat over the Suez Canal

Battle of Stalingrad

(1942 - 1943) was a major turning point in World War II, where Soviet forces defeated Nazi Germany's 6th Army, marking the halt of Germany's eastward advance and beginning their retreat; unsuccessful German attack on the city of Stalingrad

• (July 1942-February 1943) WWII battle where Soviet forces defeated the German Sixth Army at Stalingrad, which halted German expansion into the USSR and acted as a turning point at the Eastern Front

Battle of Midway Island

(June 1942) U.S. demonstration of naval superiority in the Pacific with the destruction of four Japanese aircraft carriers, stopping Japanese advancements into the Pacific

Island Hopping

A key Allied military strategy in the Pacific Theater of World War II, involving the targeted seizure of lightly defended weak Japanese-controlled islands while bypassing heavily fortified strong ones; this approach aimed to cut off supply lines, save resources, and secure airbases to move closer to Japan itself

• a WWII military strategy used by U.S. General Douglas MacArthur charcterized by attacking islands where the aggressor is weak and skipping islands where the aggressor is strong

D-Day

(June 6th, 1944) 150,000 Allied forces under U.S. General Dwight Eisenhower launched an invasion from England to the beaches of Normandy in northern France, heavily impacted the Western front and significantly pushed back the Germans

Battle of the Bulge (1944-1945)

Germany's last major offensive on the Western Front, targeting Allied lines in the Ardennes Forest. It aimed to split Allied forces to force a stalemate, resulting in the largest battle fought by the U.S. Army, ultimately depleting Germany's final resources after their defeat

• (December 1944-January 1945) Germans' final major offensive against the Allies in the Ardennes Forest (across France, Belgium, and Luxembourg), consolidated Germany's inevitable defeat

V-E Day

Victory in Europe Day celebrated on May 8, 1945, marks the formal acceptance of Nazi Germany's unconditional surrender by Allied forces, officially ending World War II in Europe

Hiroshima

President Truman ordered the U.S. Army Air Force to drop the first atomic bomb on this Japanese city on August 6, 1945, marking the beginning of the nuclear age