The Tu-4 was an unauthorized copy of the B-29 Superfortress.

Toward the end of WWII, the Soviet Union saw the need for, but lacked completely, a strategic bombing capability similar to that of the USAAF. On four occasions during 1944, B-29s made emergency landings in Soviet territory after bombing Japan. Three repairable B-29s were flown to Moscow and delivered to the Tupolev OKB enabling reverse-engineered copies to be produced in less than two years. This example is on display at the Central Museum of the Air Forces at Monino.