When was the International Day of Human Space Flight observed?

The International Day of Human Space Flight was observed across the world. The day marks the anniversary of the first ever human space flight undertaken by Yuri Gagarin, a Soviet citizen on April 12, 1961. This day is also celebrated as 'Cosmonautics Day' in Russia since 1963. Gagarin's Vostok 1 space flight executed one orbit around the Earth over 108 minutes and the spacecraft was propelled by Vostok-K launch vehicle.The day was initiated in 2011 by United Nations through resolution, A/RES/65/271.