James Clark Ross
June 2: Festa della Repubblica in Italy (1946)
June 3: Feast of Corpus Christi (Western Christianity, 2021); Anniversary of Khomeini's Death in Iran (1989); Martyrs Day in Uganda
- 1844 – The last known pair of great auks, the only modern species in the genus Pinguinus of flightless birds, were killed on Eldey, Iceland.
- 1921 – At his trial for the assassination of Talat Pasha, viewed as the main orchestrator of the Armenian genocide, Soghomon Tehlirian was acquitted after arguing: "I have killed a man, but I am not a murderer."
- 1937 – A few months after abdicating the British throne, Edward, Duke of Windsor, married American socialite Wallis Simpson (pictured) in a private ceremony in France.
- 1979 – Having invaded Uganda and deposed President Idi Amin, Tanzanian forces secured Uganda's western border, ending a seven-month war.
June 4: Trianon Treaty Day in Romania (1920)
June 5: Constitution Day in Denmark
June Rebellion in Paris
June 6: National Day of Sweden
June 7: Journalist's Day in Argentina (1810); Queen's Official Birthday in New Zealand (2021); Western Australia Day (2021)
Mosaic of Aelia Eudocia
Police activity in the aftermath of the Akihabara massacre
Burning of Gaspee
Hussein bin Ali
Alexander of Greece
June 12: Dia dos Namorados in Brazil; Independence Day in the Philippines (1898); Queen's Official Birthday in Tuvalu and the United Kingdom (2021); Loving Day in the United States (1967)
Turkish irregulars in Phocaea
Bear Flag of the California Republic
1991 eruption of Mount Pinatubo
Rudolf Nureyev in 1973
The Capture of the Forts at Taku by Fritz Neumann
June 18: Autistic Pride Day
Lockheed F-117 Nighthawk
June 19: Juneteenth in the United States (1865)
Nguyễn Cao Kỳ
June 20: World Refugee Day; Flag Day in Argentina (1820)
June 21: June solstice (03:32 UTC, 2021); Fête de la Musique; International Day of Yoga; National Indigenous Peoples Day in Canada
King George V and Queen Mary
June 23: Grand Duke's Official Birthday in Luxembourg
Pierre de Coubertin
- 1374 – An outbreak of dancing mania, in which crowds of people danced themselves to exhaustion, began in Aachen (present-day Germany) before spreading to other cities and countries.
- 1812 – Napoleonic Wars: Led by Napoleon, the French Grande Armée crossed the Neman, beginning their invasion of Russia.
- 1880 – "O Canada" (audio featured), the present-day national anthem of Canada, was first performed in Quebec City during a Saint-Jean-Baptiste Day banquet.
- 1937 – The U.S. Navy's first two fast battleships, North Carolina and Washington of the North Carolina class, were ordered from the New York and Philadelphia Naval Shipyards, respectively.
- 2010 – John Isner defeated Nicolas Mahut at the Wimbledon Championships, concluding the longest match in tennis history, which lasted 11 hours and 5 minutes over three days.
June 25: Statehood Day in Slovenia (1991)
CIA diagram of Area 51
June 26: Day of the National Flag in Romania (1848)
June 27: Seventeenth of Tammuz (Judaism, 2021)
George II at Dettingen
June 28: Vidovdan in Serbia
Crowd gathered around destroyed Serb property
June 30: Asteroid Day
Trees felled by the Tunguska explosion