This is a beautiful sheet of 4 stamps, issued in 2012 in Burundi, celebrating the 20th anniversary of Sergei Krikaliov's time aboard the space station Mir. The stamps each feature an image of Krikaliov, who was dubbed by many "the last Citizen of the USSR," as he spent 10 months aboard the Mir space station from May 1991 through March 1992 as the dissolution of the Soviet Union occurred. In addition, he has currently has spent more time in space than any other human being. Each stamp also features an image of a vehicle from various space missions, including the space shuttle Endeavor, the Soyuz-TM 7, and the landing of the STS-60.