 Einstein also learned that his name was on a list of assassination targets, with a "$5,000 bounty on his head".One German magazine included him in a list of enemies of the German regime with the phrase, "not yet hanged".Leó Szilárd (1898–1964) was a Jewish Hungarian physicist who conceived the nuclear chain reaction in 1933, patented the idea of a nuclear reactor with Enrico Fermi, and in late 1939 wrote the letter for Albert Einstein's signature that resulted in the Manhattan Project that built the atomic bomb.