April 24: Great Thursday in Eastern Christianity (2008); Republic Day in the Gambia; Genocide Remembrance Day in Armenia.
- 1800 – The Library of Congress, today the de facto national library of the United States, was established as part of an act of Congress providing for the transfer of the nation's capital from Philadelphia to Washington, D.C.
- 1877 – Russia declared war on the Ottoman Empire, starting the Russo-Turkish War.
- 1915 – The Armenian Genocide in the Ottoman Empire began with the arrest and deportation of hundreds of prominent Armenians in Constantinople.
- 1916 – Irish republicans led by teacher and political activist Patrick Pearse (pictured) began the Easter Rising, a rebellion against British rule in Ireland, and proclaimed the Irish Republic an independent state.
- 1967 – The Soviet spacecraft Soyuz 1 crashed in Siberia during its return to Earth, killing cosmonaut Vladimir Komarov, the first in-flight fatality in the history of spaceflight.
- 1990 – The Hubble Space Telescope was launched by the Space Shuttle Discovery in mission STS-31.