A unique document of the Soviet invasion of Czechoslovakia in 1968, the movie was begun as a documentary about the liberalization of Czechoslovakia and then became a record of the entry of Russian tanks into Prague. The only filmed footage of the Soviet invasion, it was seen by more than 600 million people when broadcast on television, and it was the first information that the Soviet Army had not been "invited" in. The film also includes never-before-seen scenes from the Prague Spring before the invasion.