1971 When the Soviet spacecraft Soyuz II returned to Earth, three Russian cosmonauts were found dead on board.
1972 The first leap second was added to atomic clocks, to keep pace with the slowing rotations of the Earth.
1997 After 156 years British colonial rule came to an end in Hong Kong. At dawn, 4,000 Chinese troops, backed by armoured cars and helicopters, crossed into the territory.
2000 The £1.3 million Diana Princess of Wales Memorial Playground was opened in Kensington Gardens, but no members of the Royal Family attended the ceremony.
2007 A Jeep Cherokee laden with explosives was driven into the front of Glasgow Airport in a botched terrorist attack.