Zhu Houcong, a young prince from Hubei with no direct claim through primogeniture, was installed as Ming emperor following the death of the childless Zhengde Emperor. His accession triggered the 'Great Rites Controversy,' a bitter court dispute over how to honor his birth father versus his adoptive imperial lineage, foreshadowing decades of factional strife under his rule.

Brothers Joseph-Michel and Jacques-Étienne Montgolfier, paper manufacturers by trade, demonstrated their invention publicly for the first time, sending a linen-and-paper balloon filled with hot air aloft before a crowd of townspeople and local dignitaries. The flight proved that lighter-than-air travel was possible and set off a European sensation, leading within months to the first manned flights.

U.S. Navy codebreakers had cracked Japanese naval ciphers, allowing Admiral Chester Nimitz to ambush a numerically superior fleet. Dive bombers from USS Enterprise and Yorktown caught Japanese carriers Akagi, Kaga, and Soryu refueling and rearming planes on deck, turning them into infernos within a ten-minute span. The Imperial Japanese Navy never recovered the initiative in the Pacific.

After decades of brutal colonial exploitation and a wave of unrest in early 1960, Belgium's government pushed through legislation formalizing the end of its rule over the Congo, one of Africa's largest and most resource-rich territories. The rushed timetable — independence within weeks — left fragile institutions and would soon collapse into political crisis and civil conflict under Prime Minister Patrice Lumumba.

Gemini 9A lifted off from Cape Kennedy carrying astronauts Tom Stafford and Eugene Cernan on a three-day mission to practice rendezvous and docking techniques essential for the coming Apollo program. The mission followed the failed launch of its original Agena target vehicle in May, and though docking again proved impossible due to a shroud malfunction on the substitute target, Cernan completed a grueling two-hour spacewalk that exposed the dangers of extravehicular activity.

French president François Mitterrand inaugurated the Musée d'Orsay on the banks of the Seine, transforming the disused Gare d'Orsay — built for the 1900 World's Fair — into a museum devoted to art from 1848 to 1914. The renovation, led by architect Gae Aulenti, preserved the station's iron-and-glass grandeur while housing works by Monet, Degas, Van Gogh, and Cézanne.

The day after troops cleared Tiananmen Square, a lone man carrying shopping bags stepped into the path of advancing tanks and refused to move, forcing them to halt and swerve. Photographers captured the standoff from hotel balconies, and the image circulated worldwide even as Chinese state media suppressed it domestically. His identity and ultimate fate remain unknown.

After seven weeks of student-led occupation calling for political reform, the People's Liberation Army moved into central Beijing overnight, firing on crowds and crushing barricades. By dawn on June 4, Tiananmen Square had been cleared. The government has never released a death toll, and the massacre remains one of the most heavily censored topics in China.