Cosmonautic's Day is a holiday celebrated (mainly in Russia) every April 12 to commemorate the first manned earth orbit. It was established in the USSR on April 9, 1962.
It is celebrated in honor of the historic first manned space flight made on April 12, 1961 by 27 year old Russian cosmonaut Yuri Alekseevich Gagarin of the USSR, who made one complete orbit around the Earth (lasting 1 h 48 min) aboard the spacecraft Vostok 1.
It was an instant and overwhelming success for the Soviet space program, and resonated loudly all over the globe. Gagarin immediately became not just a national hero of the Soviet Union, but a global hero too. Major newspapers all around the globe published his biography and details of his flight. Moscow (and other large cities in USSR) held parades, the scale of which was second only to WWII Victory Parades. The joy of millions was so overwhelming that people cried and danced in the streets. Strangers greeted and kissed each other.
Gagarin was escorted in a long motorcade of high-ranking officials through the streets of Moscow to the Kremlin where, in a lavish ceremony, he was awarded the highest Soviet honor, the title of Hero of Soviet Union, by the Soviet leader Nikita Khrushchev.
On Cosmonautic's Day, the commemoration ceremony starts in the city of Korolyov, near Gagarin's statue. Participants then proceed under police escort to Red Square for a visit to Gagarin's grave in the Kremlin Wall Necropolis, and continue to Cosmonauts Alley, near the Monument to the Conquerors of Space. Finally, the festivities are concluded with a visit to the Novodevichy Cemetery.