Mirror for a Hero(1988)

Original title: Зеркало для героя

Sergei and Andrei are walking through a city park and see that a film shoot set just post World War II is taking place . They climb over the park fence to get a better view but hit some cable lying on the ground and find themselves in the past - on May 8, 1949, a day which they seem doomed to relive over and over again.