Wikipedia:Selected anniversaries/April 1
- 1789 - The U.S. House of Representatives held its first quorum in New York City and elected Frederick Muhlenberg (pictured) as the first Speaker.
- 1826 - The internal combustion engine was patented by Samuel Morey.
- 1918 - The Royal Naval Air Service and the Royal Flying Corps merged to form the Royal Air Force, the air force branch of the British Armed Forces.
- 1939 - Generalísimo Francisco Franco of the Spanish State proclaimed victory in the Spanish Civil War.
- 1957 - The BBC television programme Panorama ran a mockumentary about Spaghetti trees.
- 1973 - Project Tiger, a wildlife conservation project to protect the Bengal Tiger, was launched at Jim Corbett National Park, India.
- 1997 - Comic strip switcheroo: Cartoonists of popularly syndicated comic strips swapped cartoons for the day.