Copy-paste from Wikipedia:
The Unknown War (Russian: “Великая Отечественная Война” (The Great Patriotic War) or “Неизвестная война” (The Unknown War) is an American documentary television series. The 20-part series documents the World War II conflict between Nazi Germany and the Soviet Union. Each episode is about 48 minutes long, similar in format to The World at War. The footage was edited from over 3.5 million feet of film taken by Soviet camera crews from the first day of the war, 22 June 1941, to the Soviet entry into Berlin in May 1945. Most of these films have never been seen outside this documentary series.
The series is hosted by Academy Award Winner Burt Lancaster, who spent three weeks in eight cities in the USSR for location filming. Film footage from Soviet archives comprises a major portion of the series, supplemented by film from both the United States and British archives. Appearing in exclusive interviews would be Russian Commanders like Georgi Zhukov and Vasily Chuikov.
The series was produced with Soviet cooperation after the release of The World at War, which the Soviet government felt paid insufficient attention to their part in World War II. Released in 1978, The Unknown War is sympathetic to the Soviet struggle against Nazi Germany. It was quickly withdrawn from TV airings after it ran in 1978, possibly because its tone was at odds with the growing tensions between East and West after the Soviet intervention in Afghanistan. Later it returned to airings on cable, including A&E, the History Channel and YouTube.