This Day @ Law
Sandra Day O'Connor confirmed as first female US Supreme Court justice

On September 21, 1981, the US Senate approved the nomination of Sandra Day O’Connor to the US Supreme Court by a vote of 99-0, making her the first female Supreme Court justice.

Leran more about Justice O'Connor from the OYEZ website at Northwestern University.

Ferdinand Marcos declares martial law in the Philippines

On September 21, 1972, President Ferdinand Marcos signed Proclamation 1081, implementing martial law in the Philippines. Marcos used the proclamation not only to suppress a communist insurgency but to eliminate political opponents as well. He remained in power until he was forced from office and into exile by the People Power Revolution in 1986.