May 10

Christopher Columbus sights the Cayman Islands, naming them "Las Tortugas" for the abundance of sea turtles.

Christopher Columbus sighted the Cayman Islands during his fourth and final voyage, naming them "Las Tortugas," Spanish for "the turtles," after the abundant sea turtles he observed nesting along the shores. The name Cayman, derived from a Carib word for crocodile referring to the islands' resident iguanas, later prevailed once permanent settlement began.

The British Parliament passes the Tea Act, legislation intended to aid the East India Company that ultimately sparked the Boston Tea Party.

The British Parliament passed the Tea Act, granting the financially struggling East India Company a lucrative monopoly on tea sales directly to the American colonies while retaining a small existing tax. Colonists viewed the arrangement as an unacceptable assertion of British taxation authority and a threat to local merchants, a grievance that directly sparked the Boston Tea Party protest later that year.

Louis XVI and Marie Antoinette ascend to the French throne following the death of Louis XV.

Louis XVI and Marie Antoinette ascended to the French throne following the sudden death of Louis XV from smallpox, inheriting a kingdom already burdened by deep financial troubles, an outdated tax system, and growing social unrest that would culminate in revolution and their own executions less than two decades later.

Colonial militia under Ethan Allen and Benedict Arnold capture Fort Ticonderoga from British forces early in the American Revolutionary War.

Colonial militia forces led jointly, and contentiously, by Ethan Allen's Green Mountain Boys and Benedict Arnold captured the lightly defended British Fort Ticonderoga in a surprise dawn raid early in the American Revolutionary War. The fort's substantial captured artillery was later hauled overland by Henry Knox to Boston, helping force the eventual British evacuation of that city.

The First Transcontinental Railroad is completed at Promontory Summit, Utah, with the ceremonial driving of the golden spike.

Railroad officials drove a ceremonial golden spike at Promontory Summit, Utah, marking the triumphant completion of the First Transcontinental Railroad and physically linking the eastern and western United States by rail for the first time. The achievement, built largely by Chinese and Irish immigrant laborers, dramatically transformed American trade, travel, and westward settlement patterns.

The first official Mother's Day observance in the United States is held in Grafton, West Virginia.

The first official Mother's Day observance in the United States was held at Andrews Methodist Episcopal Church in Grafton, West Virginia, organized by activist Anna Jarvis in memory of her recently deceased mother's earlier community service work. The modest local event launched a national campaign that led to the holiday's formal congressional recognition just six years later, in 1914.

Winston Churchill becomes British prime minister on the same day Germany launches invasions of France, the Netherlands, Belgium, and Luxembourg.

Winston Churchill became British prime minister on the very same day Nazi Germany launched simultaneous invasions of France, Belgium, the Netherlands, and Luxembourg, thrusting him immediately into leading Britain through the darkest and most perilous early phase of World War II following the resignation of the discredited Neville Chamberlain.

Nelson Mandela is inaugurated as South Africa's first Black president, following the country's first fully democratic elections.

Nelson Mandela was inaugurated as South Africa's first Black president before a jubilant crowd of dignitaries in Pretoria, following the country's first fully democratic, multiracial elections held weeks earlier. The moment marked the formal end of the decades-long apartheid era of institutionalized racial segregation and a historic milestone in the nation's difficult transition to democracy.

A sudden blizzard strikes climbers near the summit of Mount Everest, killing eight people in one of the deadliest single-day disasters on the mountain.

A sudden, violent blizzard struck climbers descending from the summit of Mount Everest during an unusually crowded climbing season, killing eight people in a single catastrophic day, one of the deadliest disasters in the mountain's history at the time. The tragedy was later chronicled in journalist Jon Krakauer's bestselling book "Into Thin Air."

One World Trade Center becomes the tallest building in the Western Hemisphere upon completion of its spire.

One World Trade Center in Lower Manhattan became the tallest building in the Western Hemisphere upon the topping-out of its dramatic 408-foot spire, rising symbolically on the site of the original Twin Towers destroyed in the September 11, 2001, terrorist attacks nearly twelve years earlier.