feb 22, 1961 - 1961
February 1 - U.S. launches the Minuteman I missile.
September 1 - U.S.S.R. resumes nuclear testing.
September 15 - U.S. resumes nuclear testing.
October 31 - U.S.S.R. explodes the world's largest nuclear bomb, with a yield of 58 megatons.
Added to timeline:
atomic and nuclear physics