Berlin Tunnel 21 (1981)

Lt. Sandy Mueller (Richard Thomas) is an American soldier living in Germany during the completion of the Berlin Wall. Determined to bypass the imposing structure, Mueller partners with Emerich Weber (Horst Buchholz), a German engineer, to build a secret underground tunnel to East Berlin. By risking everything, Mueller and Emerich undertake the perilous endeavor in order to smuggle those trapped in the East to freedom. With the authorities always on guard, the two men are in constant danger.