Between Mount Rushmore National Memorial and Ellsworth Air Force Base in South Dakota, remnants of the Berlin Wall stand as a reminder that freedom requires vigilance and that the principles of freedom associated with Mount Rushmore's four presidents helped play a pivotal role in destroying the wall, a symbol of Communist tyranny. In 1980, Swiss health care lecturer Dr. Angelo Sargenti toured Ellsworth's missile wing and bomb wing and told a colonel that the work being done there allowed people in Switzerland to live in freedom. Tribute is paid to the thousands of military personnel who lost their lives in the Cold War and to those who risked their lives in it. On June 22, 1990, in a formal ceremony attended by foreign ministers from the United States, France, Great Britain, the Soviet Union, and both Germanys, a crane hoisted the Checkpoint Charlie guardhouse out of Friedrichstrasse. New border crossings at the wall opened on November 9, 1989, with most activity along the approximate two-mile section between the Brandenburg Gate and Checkpoint Charlie, an East Berlin crossing in the American sector, and Rapid City's two Berlin Wall segments came from this area.