Event:
Japan reports on the International Nuclear Event Scale that they've upgraded the leak of radioactive water at the Fukushima nuclear disaster site to Level 3, a 'serious incident'
More Notable Events on August 21:
1993 NASA loses contact with Mars Observer
1989 Voyager 2 begins a flyby of planet Neptune
1968 Democratic Convention opens in Chicago
1968 Warsaw Pact forces enter Czechoslovakia to end reform movement
1897 Oldsmobile begins operation as a General Motors Corp division