April 7, 1940 (80 years ago)
•Booker T. Washington becomes the first African American to be depicted on a United States postage stamp.

April 7, 1948 (72 years ago)
•The World Health Organization is established by the United Nations.

April 7, 1978 (42 years ago)
•Development of the neutron bomb is canceled by U.S. President Jimmy Carter.