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Revolutionized transportation by being the first truly affordable, mass-produced automobile, thanks to Henry Ford's implementation of the moving assembly line. Designed to be simple, durable, and easy to operate, its low cost (dropping from $850 to $290 by 1924) made car ownership accessible to middle-class Americans, fundamentally changing society and spurring infrastructure development like roads and gas stations.
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The Zimmermann Telegram was a secret German message in 1917 proposing a military alliance with Mexico against the U.S. during World War I, offering Mexico the return of territories like Texas, Arizona, and New Mexico
. Intercepted and decoded by British intelligence, its public release in the U.S. inflamed anti-German sentiment, pushing America toward declaring war on Germany in April 1917, alongside Germany's resumption of unrestricted submarine warfare -
A military agreement signed by Germany and the Allies on November 11, 1918, that halted fighting on the Western Front at 11 a.m., effectively ending the Great War and leading to celebrations but also resentment over harsh German surrender terms, which included immediate withdrawal from occupied territories and surrendering vast amounts of military equipment, setting the stage for the final Treaty of Versailles.
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The 19th Amendment, ratified in 1920,
prohibits the U.S. government and states from denying citizens the right to vote based on sex, effectively granting women suffrage after a long fight. It states, "The right of citizens of the United States to vote shall not be denied or abridged by the United States or by any State on account of sex". -
Charles Lindbergh's historic 1927 flight involved flying solo and nonstop from New York to Paris in his custom-built, single-engine plane, The Spirit of St. Louis, taking 33.5 hours to cover 3,600 miles and battling severe fatigue, cold, and fog to become an international hero and usher in a new era of aviation.
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Marked the beginning of the 1929 stock market crash, a day of extreme panic selling on Wall Street where a record 12.9 million shares were traded as nervous investors feared a market collapse, triggering the severe economic downturn known as the Great Depression.
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President Franklin D. Roosevelt's series of programs and reforms during the 1930s Great Depression, focusing on the "Three Rs": Relief for the jobless and poor, Recovery of the economy, and Reform of the financial system to prevent future crises.
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Adolf Hitler was appointed
Chancellor of Germany on January 30, 1933, by President Paul von Hindenburg through a legal, constitutional process. This appointment was the result of a series of political compromises and backroom deals by conservative politicians who believed they could control Hitler and his Nazi Party. -
A 1938 settlement between Germany, Great Britain, France, and Italy that allowed Germany to annex the Sudetenland, a border region of Czechoslovakia with a large German-speaking population, in exchange for promises of peace, a policy known as appeasement.
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Hitler's invasion of Poland on September 1, 1939, launched World War II, using swift "Blitzkrieg" tactics with tanks, airpower, and coordinated attacks that overwhelmed Polish defenses
. Germany invaded from the north, south, and west, followed by a Soviet invasion from the east, quickly resulting in Poland's defeat and division, and initiating the systematic persecution and extermination of its people under Nazi occupation. -
Pearl Harbor was the site of a surprise Japanese aerial attack on the U.S. Pacific Fleet in Hawaii on December 7, 1941, a devastating assault that crippled U.S. naval power, killed over 2,400 Americans, and directly led to the United States' entry into World War II the next day. Hundreds of Japanese fighter planes struck the base, sinking or damaging numerous battleships and aircraft, solidifying America's resolve to fight.
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The massive Allied amphibious invasion of Normandy, France (Operation Overlord), the largest seaborne invasion in history, marking a pivotal turning point in WWII by beginning the liberation of Nazi-occupied Western Europe, with over 150,000 troops landing on five beaches (Utah, Omaha, Gold, Juno, Sword) to establish a foothold against German forces.
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The cities of
Hiroshima and Nagasaki were the sites of the only uses of nuclear weapons in armed conflict, when the United States dropped atomic bombs on them. The bombings caused immense destruction and loss of life, leading to Japan's unconditional surrender and the end of the war. -
Formed in 1945 after World War II by 50 nations meeting in San Francisco to draft the UN Charter, aiming to prevent future wars, protect human rights, and foster global cooperation.
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An influential 8,000-word message sent by U.S. diplomat
George F. Kennan from Moscow in February 1946, explaining Soviet behavior as driven by a deep-seated insecurity and aggressive expansionism rooted in Marxist ideology, proposing the strategy of "containment" to counter Soviet influence, and laying the groundwork for U.S. Cold War policy. -
Formed in 1949 by 12 North American and European nations as a collective defense alliance to counter Soviet expansion after World War II.
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A massive, state-directed effort combining espionage, stolen designs (especially from the "Fat Man" bomb via spy Klaus Fuchs), and internal scientific work, culminating in their first successful test, "Joe-1," in Kazakhstan on August 29, 1949, significantly accelerating the Cold War nuclear arms race.
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A brutal Cold War conflict where Communist North Korea, backed by China and the Soviet Union, invaded South Korea, supported by a UN coalition led by the United States, to unify the peninsula under communist rule.
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U.S. Supreme Court case that unanimously declared state-sponsored segregation in public schools unconstitutional, overturning the "separate but equal" doctrine from Plessy v. Ferguson (1896). The ruling, led by Chief Justice Earl Warren, established that segregated schools inherently violate the Fourteenth Amendment's Equal Protection Clause because separate facilities are never truly equal, providing a major catalyst for the American Civil Rights Movement.
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A prolonged, costly conflict pitting communist North Vietnam (supported by the Soviet Union and China) against South Vietnam (supported by the United States) in a struggle for Vietnamese unification, intensified by Cold War tensions.
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Rosa Parks refused a bus driver's order to give up her seat in the "colored section" to a white passenger, a direct defiance of segregation laws. Her quiet but firm "No" led to her arrest, sparking the year-long Montgomery Bus Boycott, a pivotal event that mobilized the Civil Rights Movement and ultimately led to the Supreme Court ruling that segregated buses were unconstitutional.
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A tense, 13-day standoff in October 1962 between the U.S. and Soviet Union, triggered by Soviet nuclear missile placements in Cuba, just 90 miles from Florida, discovered by U.S. spy planes.
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President John F. Kennedy was assassinated on November 22, 1963, in Dallas, Texas, shot from the Texas School Book Depository by Lee Harvey Oswald, shocking the nation and ushering in Lyndon B. Johnson as President, profoundly impacting American politics, media, and public trust, fostering deep-seated conspiracy theories, accelerating the Civil Rights Movement, and leading to the 25th Amendment for presidential succession.
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A 1964 congressional act that gave President Lyndon B. Johnson broad authority to take "all necessary measures to repel any armed attack against the forces of the United States and to prevent further aggression" in Southeast Asia.
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Astronauts Neil Armstrong and Buzz Aldrin walked on the lunar surface in the Sea of Tranquility, with Armstrong famously saying, "That's one small step for man, one giant leap for mankind," while Michael Collins orbited above in the command module, marking a pivotal moment in the Space Race.
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The Watergate break-ins were a series of burglaries, most notably on June 17, 1972, at the Democratic National Committee (DNC) headquarters in the Watergate complex, where operatives linked to President Richard Nixon's re-election campaign were caught planting listening devices and stealing documents
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Richard Nixon resigned as U.S. President on August 9, 1974, due to the
Watergate scandal, becoming the only U.S. president to do so; he faced almost certain impeachment by Congress for obstructing justice and abusing power after key tapes proved his involvement in the cover-up, leading him to step down to avoid removal and allow for national healing, with Vice President Gerald Ford succeeding him and later issuing a controversial pardon. -
The crucial step towards today's internet came in 1991 when Tim Berners-Lee created the World Wide Web (WWW), making it user-friendly with hyperlinks and browsers, opening it for public use and sparking massive growth.
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Marked the symbolic end of the Cold War, as East Germany unexpectedly opened its borders, allowing citizens to freely travel to the West after massive protests against communist rule. Triggered by a bureaucratic error during a press conference, East Germans flooded the checkpoints, leading overwhelmed guards to open the gates, resulting in joyous reunions and the physical dismantling of the wall, paving the way for German reunification in 1990.
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Terrorists from the extremist group al-Qaeda hijacked four commercial airplanes and carried out coordinated suicide attacks against targets in the United States.
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The pandemic caused severe social and economic disruption around the world, including the largest global recession since the Great Depression.