sentences:  With the potential of making a fission-based atomic weapon and the threat of war in Europe, this caused anxiety in many, Leó Szilárd for example, that Germany would develop an atomic weapon.As a result of two meetings with Albert Einstein, the first with Szilárd and Eugene Wigner and the second with Szilárd and Edward Teller, Einstein signed the Einstein–Szilárd letter to President Franklin Delano Roosevelt (FDR) in August.World War II broke out in Europe in September.