Crusaders from the Fourth Crusade broke through Constantinople’s walls and entered the great city.
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Rock Around The Clock by Bill Haley and His Comets was recorded.
Israeli Knesset chose April 13 as the official Holocaust Remembrance Day.
The world's first person visited space.
The first Space Shuttle mission was launched.
Jonas Salk's Polio vaccine tested by Jonas Salk was given final approval by the US Food and Drug Administration.
