In the background of International aerospace salon (MAKS) there is an aircraft park of abandoned airplanes. Unfortunately, the territory is surrounded by a fence but many things can still be seen. The legendary Buran is located here as well, by the way.
The Sukhoi Su-15 (NATO reporting name 'Flagon') was a twin-engined supersonic interceptor developed by the Soviet Union in the 1960s.
The Su-15UT (NATO "Flagon-C"). Airplanes like Su-15 had been in arsenal of Russia till 1994.
The Su-15s are closely related to interception of those planes that have violated the air space of the USSR. One such case occurred in 1978 in Karelia when Boeing-707 that flied from Paris to Anchorage violated the Soviet border near Murmansk. Pilots of Boeing-707 were asked to land but with no success and the plane was brought down.