On 12 April 1961, Russian cosmonaut Yuri Gagarin became the first human to enter outer space.
Upon his landing, Gagarin became a hero of the Soviet Union and an international celebrity, and his triumph impelled the United States to ramp up its effort to reach space.
A month after Gagarin's legendary flight, astronaut Alan Shepard flew the first successful U.S. mission into space and back. According to Scientific American, the U.S. finally put a man into orbit on 20 February 1962, when John Glenn's Friendship 7 craft circled the globe three times.
Gagarin never returned to space after his historic first flight. He died in a jet crash while training to pilot a fighter craft on 27 March 1968.
You can view Google's commemorative logo (below), which is dedicated to Yuri Gagarin's flight into space. Visit Google.com on April 12 to see the doodle for yourself and learn more about Gagarin. Also check out YouTube's video honoring 50 years of human spaceflight.