Event:
Levi Strauss markets blue jeans with copper rivets, price $13.50 doz
More Notable Events on May 20:
1992 India launches its 1st satellite independently
1989 China declares martial law in Beijing
1954 Chiang Kai-shek becomes president of Nationalist China
1940 Igor Sikorsky unveils his helicopter invention
1932 Amelia Earhart leaves Newfoundland 1st woman fly solo across Atlantic
