March 18

The Roman Senate proclaims Caligula emperor after annulling the will of his predecessor Tiberius.

Following the death of Emperor Tiberius, the Roman Senate proclaimed his 24-year-old great-nephew Gaius, nicknamed Caligula, as emperor, annulling Tiberius's will that would have shared power with another heir. Caligula's initially popular reign later descended into infamous cruelty and erratic behavior before his assassination four years later.

Jacques de Molay, the last Grand Master of the Knights Templar, is burned at the stake in Paris.

Jacques de Molay, the final Grand Master of the Knights Templar, was burned at the stake in Paris on charges of heresy after years of imprisonment and torture under King Philip IV of France, who sought to seize the order's wealth. His death effectively ended the once-powerful medieval military order.

The British Parliament repeals the unpopular Stamp Act, easing tensions with the American colonies.

The British Parliament repealed the 1765 Stamp Act, which had imposed direct taxes on printed materials in the American colonies and sparked fierce colonial resistance. While celebrated in the colonies, Parliament simultaneously passed the Declaratory Act asserting its right to legislate for the colonies, setting the stage for future conflict.

Parisians rise up and establish the revolutionary Paris Commune, which briefly governed the city.

Parisians, angered by the national government's attempt to seize the National Guard's cannons and by the hardships of the recent siege by Prussia, rose in revolt and established the Paris Commune, a radical socialist government that controlled the city for about two months before being violently suppressed.

An Allied naval assault on the Dardanelles fails disastrously, with three battleships sunk, during World War I.

British and French warships attempted to force passage through the Dardanelles strait to threaten Constantinople but struck a minefield, losing three battleships and suffering heavy damage to others. The costly failure led Allied commanders to instead plan the ill-fated land invasion at Gallipoli.

Mexico nationalizes its foreign-owned oil industry, establishing the state company that became Pemex.

President Lazaro Cardenas signed a decree nationalizing Mexico's foreign-owned oil companies after a bitter labor dispute, expropriating British and American holdings and creating the state-run company Pemex. The move, still celebrated annually as a milestone of Mexican economic sovereignty, prompted a temporary international boycott of Mexican oil by the affected foreign corporations and their governments.

Adolf Hitler and Benito Mussolini meet at the Brenner Pass, cementing their wartime alliance.

Adolf Hitler met Benito Mussolini at the Brenner Pass on the Italian-Austrian border, seeking to secure Italian cooperation and passage of German troops through Italian territory as World War II expanded. The meeting reinforced the Axis alliance ahead of Germany's invasions later that year.

France and Algerian nationalists sign the Evian Accords, agreeing to end the Algerian War of Independence.

French President Charles de Gaulle's government and representatives of Algeria's National Liberation Front signed the Evian Accords, agreeing to a ceasefire and a referendum on Algerian self-determination. The agreement effectively ended the brutal eight-year Algerian War of Independence, though a formal ceasefire took effect the next day.

Soviet cosmonaut Alexei Leonov becomes the first person to walk in space.

Soviet cosmonaut Alexei Leonov exited his Voskhod 2 spacecraft tethered by a cable, becoming the first human to walk in space. His spacesuit swelled in the vacuum, nearly preventing his return to the capsule, in a harrowing episode not disclosed publicly until decades later.

Russia and Crimean officials sign a treaty formalizing Russia's annexation of Crimea, a move most of the world refused to recognize.

Russian President Vladimir Putin signed a treaty with Crimean officials formalizing the peninsula's annexation from Ukraine, following a disputed referendum held under Russian military presence. The international community broadly condemned the annexation as illegal, imposing sanctions that strained relations between Russia and the West for years.