While in Cutchogue on August 2, 1939, pipe-smoking Einstein was visited by fellow Jewish physicists from Hungary Leó Szilárd (who had produced a nuclear chain reaction in a laboratory at Columbia University) and Edward Teller (both prompted by Niels Bohr), and dictated the famous Letter to President Roosevelt, alerting him to the new developments in nuclear physics and hinting that the Germans might be working on an atomic bomb, urging him to launch his own program. The letter is widely credited with setting in motion the Manhattan Project, the US government effort that built the first atomic bomb.