March 5

King Henry VII of England grants explorer John Cabot letters patent authorizing a voyage to find new lands, leading to Cabot's landing in North America the following year.

King Henry VII authorized Venetian navigator John Cabot to sail west in search of new lands on England's behalf, motivated by the desire to compete with Spain and Portugal's overseas discoveries. Cabot's subsequent 1497 voyage, which reached the coast of present-day Newfoundland, laid the groundwork for later English claims in North America.

British soldiers fire on a crowd of colonists in Boston, killing five people in what becomes known as the Boston Massacre.

Tensions between British troops occupying Boston and local colonists erupted into violence when soldiers fired into a taunting crowd, killing five men including Crispus Attucks, often considered the first casualty of the American Revolution. Colonial propagandists, including Paul Revere's engraving, used the incident to inflame anti-British sentiment.

George Westinghouse patents the railway air brake, a major advance in railroad safety.

George Westinghouse patented an air brake system allowing train engineers to simultaneously control brakes on every car in a train, a dramatic improvement over earlier manual systems. The invention greatly improved railroad safety and efficiency, becoming standard equipment and forming the basis of the industrial empire Westinghouse built.

The Nazi Party wins 43.9 percent of the vote in German elections, enough to soon pass the Enabling Act and seize dictatorial power.

In the last relatively free German election before Hitler's consolidation of power, the Nazi Party won a plurality but fell short of an outright majority despite widespread intimidation following the Reichstag fire. The result nonetheless gave Hitler's coalition enough seats to push through the Enabling Act weeks later, legalizing dictatorial rule.

Anti-communist Spanish Republican forces seize control of the government in a coup, hastening the end of the Spanish Civil War.

A group of anti-communist Republican officers led by Colonel Segismundo Casado seized control of Madrid from Juan Negrin's government, hoping to negotiate more favorable surrender terms with Franco's Nationalists. The coup fractured remaining Republican resistance and hastened the fall of Madrid weeks later, effectively ending the Spanish Civil War.

Soviet officials sign an order authorizing the execution of nearly 26,000 Polish military officers and intellectuals in what becomes known as the Katyn massacre.

Soviet secret police chief Lavrentiy Beria's proposal to execute nearly 22,000 Polish officers, intellectuals, and other prisoners was approved by Stalin and the Politburo. The resulting Katyn massacre, long denied by Soviet authorities and blamed on Nazi Germany, was not officially acknowledged by Russia until 1990.

Winston Churchill delivers his famous "Iron Curtain" speech, warning of Soviet domination of Eastern Europe.

Speaking at Westminster College in Missouri with President Truman present, Winston Churchill warned that "an iron curtain has descended across the Continent," describing Soviet control over Eastern Europe. The speech is widely regarded as a defining early statement of Cold War tensions between the Western allies and the Soviet Union.

Soviet leader Joseph Stalin dies after his stroke four days earlier, ending nearly three decades of rule.

Joseph Stalin died at his dacha four days after suffering a stroke, having ruled the Soviet Union with absolute authority since the late 1920s through forced collectivization, purges, and victory in World War II. His death triggered a power struggle eventually won by Nikita Khrushchev, who later denounced Stalin's crimes.

BOAC Flight 911 breaks apart in turbulence near Mount Fuji, Japan, killing all 124 people aboard.

British Overseas Airways Corporation Flight 911, a Boeing 707 carrying mostly Japanese passengers on a sightseeing route near Mount Fuji, broke apart in extreme clear-air turbulence caused by mountain waves. All 124 people aboard were killed in one of the deadliest turbulence-related air disasters in aviation history.

The Treaty on the Non-Proliferation of Nuclear Weapons enters into force after ratification by 43 nations.

The Treaty on the Non-Proliferation of Nuclear Weapons took effect after ratification by dozens of nations, establishing a framework in which recognized nuclear powers pledged disarmament efforts while other states agreed to forgo developing nuclear weapons. It remains the cornerstone international agreement governing global nuclear arms control.