Uruguay: Proclamation of the First Constitution
1334 - The bishop of Florence blesses the first foundation stone for the new campanile (bell tower) of the Florence Cathedral, designed by the artist Giotto di Bondone.
1656 - Polish-Lithuanian forces clash with Sweden and its Brandenburg allies in the start of what is to be known as The Battle of Warsaw which ends in a decisive Swedish victory.
1857 - Louis Faidherbe, French governor of Senegal, arrives to relieve French forces at Kayes, effectively ending El Hajj Umar Tall's war against the French.
1862 - First ascent of Dent Blanche, one of the highest summits in the Alps.
1863 - American Civil War: Battle of Fort Wagner/Morris Island – the first formal African American military unit, the 54th Massachusetts Volunteer Infantry, fails in their assault on Confederate-held Battery Wagner.
1870 - The First Vatican Council decrees the dogma of papal infallibility.
1914 - The U.S. Congress forms the Aviation Section, U.S. Signal Corps, giving definite status to aircraft within the U.S. Army for the first time.
1925 - Adolf Hitler publishes his personal manifesto Mein Kampf.
1936 - In Spanish Morocco, military rebels attempt a coup d'état against the legitimacy of the Spanish government. This will lead to the Spanish Civil War.
1942 - World War II: the Germans test fly the Messerschmitt Me-262 using only its jet engines for the first time.
1944 - World War II: Hideki Tojo resigns as Prime Minister of Japan due to numerous setbacks in the war effort.
1965 - Russian satellite Zond 3 launched.
1966 - Gemini 10 launched.
1968 - The Intel Corporation is founded in Santa Clara, California
1969 - After a party on Chappaquiddick Island, Senator Ted Kennedy from Massachusetts drives an Oldsmobile off a bridge and his passenger, Mary Jo Kopechne, dies.
1976 - Nadia Comăneci became the first person in Olympic Games history to score a perfect 10 in gymnastics at the 1976 Summer Olympics.
1982 - 268 campesinos ("peasants" or "country people") are slain in the Plan de Sánchez massacre in Ríos Montt's Guatemala.
1984 - McDonald's massacre in San Ysidro, California: in a fast-food restaurant, James Oliver Huberty opens fire, killing 21 people and injuring 19 others before being shot dead by police.
1984 - Beverly Lynn Burns becomes first female Boeing 747 airline captain.
1986 - A tornado is broadcast live on KARE television in Minnesota when the station's helicopter pilot makes a chance encounter.
1992 - The ten victims of the La Cantuta massacre disappear from their university in Lima.
1994 - The Amia (Jewish Communal Center) bombings occurred in Buenos Aires killing 85 people (mostly Jewish) and injuring 300.
1995 - On the Caribbean island of Montserrat, the Soufriere Hills volcano erupts. Over the course of several years, it devastates the island, destroying the capital and forcing most of the population to flee.
1996 - Storms provoke severe flooding on the Saguenay River, beginning one of Québec's costliest natural disasters ever.
1996 - Battle of Mullaitivu, Tamil Tigers carried out this attack killing over 1200 Sri Lankan Army soldiers and capturing the base, biggest single lost to Sri Lankan Army ever.
2005 - Indo-US civilian nuclear agreement, first public joint statement by Indian Prime Minister Manmohan Singh and the then U.S. President George W. Bush.