https://www.history.com/this-day-in-history/the-first-atomic-bomb-test-is-successfully-exploded?cmpid=email-hist-tdih-2023-0 [login to see] 3&om_rid=
On July 16, 1945, at 5:29:45 a.m., the Manhattan Project yields explosive results as the first atom bomb is successfully tested in Alamogordo, New Mexico.
Plans for the creation of a uranium bomb by the Allies were established as early as 1939, when Italian emigre physicist Enrico Fermi met with U.S. Navy department officials at Columbia University to discuss the use of fissionable materials for military purposes. That same year, Albert Einstein signed a letter to President Franklin Roosevelt supporting the theory that an uncontrolled nuclear chain reaction had great potential as a basis for a weapon of mass destruction. In February 1940, the federal government granted a total of $6,000 for research. But in early 1942, with the United States now at war with the Axis powers, and fear mounting that Germany was working on its own uranium bomb, the War Department took a more active interest, and limits on resources for the project were removed.