621: Battle of Nineveh: Emperor Heraclius of the Byzantine Empire defeats a large Persian army, effectively leading to the end of the Persian Sasanian dynasty and the rise of the Muslim Caliphate.
1453: The capture of Constantinople: The Ottoman Empire, led by Sultan Mehmed II, captures Constantinople (now Istanbul) after a siege of 53 days, officially ending the Byzantine Empire.
1727: The first successful appendectomy is performed by Claudius Amyand, a French surgeon working in London, on a 15-year-old boy.
1790: The Rhode Island Convention ratifies the United States Constitution, making it the 13th state to do so and completing the necessary number of states for the Constitution to go into effect.
1848: Wisconsin is admitted to the United States as the 30th state.
1869: The completion of the First Transcontinental Railroad is celebrated at Promontory Summit, Utah, as the Union Pacific and Central Pacific railroads meet, linking the East and West coasts of the United States.
1914: The Canadian Pacific Ocean Liner Empress of Ireland sinks in the St. Lawrence River after colliding with the Norwegian collier Storstad, resulting in the deaths of over 1,000 people.
1953: Edmund Hillary and Tenzing Norgay reach the summit of Mount Everest, becoming the first humans to do so.
1961: The United States Federal Communications Commission (FCC) approves the first commercial relay communications satellite, Telstar 1, which will enable live transatlantic television broadcasts.
1975: The European Space Agency (ESA) is established with the signing of the ESA Convention in Paris.
1985: The European Economic Community (EEC) agrees to admit Spain and Portugal as new members, effective from January 1, 1986.
1999: The Nigerian constitutional referendum approves the country's new constitution, paving the way for democratic elections and marking an end to military rule.
2011: The wedding of Prince William and Catherine Middleton takes place at Westminster Abbey in London, attracting global media attention.