Wikipedia:Selected anniversaries/June 27
- 678 - Saint Agatho began his reign as Pope.
- 1846 - Irish potato famine: An Irish newspaper ran a story about a new potato blight.
- 1954 - The world's first large-scale nuclear power plant opened in Obninsk, in the Soviet Union.
- 1967 - The world's first electronic automatic teller machine was installed in Enfield Town, London.
- 1969 - The Stonewall riots began in New York City, starting the modern gay rights movement.
- 1979 - Muhammad Ali (pictured) announced his retirement from boxing.
- 1986 - The International Court of Justice ruled against the United States in Nicaragua v. United States.
- 1991 - The Ten-Day War starts in Slovenia, two days after that country's declaration of independence from Yugoslavia.