Helmstedt

 was a German town. In the 1980s, it was part of East Germany, on the border of West Germany. On 6 November 1989, in an alternate timeline created by Elder Gods, the Soviet army amassed in the town, prompting the United States of America to drop a tactical nuclear bomb on the town. This prompted World War III, until the Seventh Doctor negated the timeline. (AUDIO: Protect and Survive)