On April 12, 1961, Gagarin became the first human to travel into space (see Vostok 1). From 1962 he served as a deputy to the Supreme Soviet. He was killed in a crash of a MiG-15 on a routine training flight near Moscow.
Although Gagarin is indisputably the first man to survive space travel, there is a conspiracy theory that the Russians had previously launched two human beings into orbit prior to Gagarin, but both cosmonauts died enroute. The Soviet government then supposedly suppressed this information to prevent bad publicity for their space program.
See also: Space Race