Checkpoint Charlie was the principal gateway for Allies, other non-Germans and diplomats between the two Berlins from 1961 to 1990. Unfortunately, this potent symbol of the Cold War has become a tacky tourist trap where uniformed actors pose for tips in front of a replica guardhouse. The one redeeming aspect is the free temporary open-air exhibit chronicling Cold War history along Friedrichstrasse, Zimmerstrasse and Schützenstrasse.