When Yuri Gagarin became the first human in space, the reaction was, if anything, more electric than when Sputnik launched. On April 12, 1961, the Soviets successfully sent cosmonaut Gagarin into space and brought him back alive. | American Experience | PBS

On International Day of Human Space Flight, a look at the life of Russian cosmonaut Yuri Gagarin, the first person to enter outer space. | Reuters