Prague

Prague was a city in Czechoslovakia and, later, the Czech Republic in Eastern Europe on Earth. The first eight incarnations of the Doctor and their various companions all visited the city during its history.

In the 30th century, the Fourth Doctor and Romana visited the city and discovered that Charles University was experimenting with Zygma energy. (ST: The End of Now)

The Eighth Doctor and Charley Pollard once visited the city at a time when the city was enclosed within a dome. (ST: War in a Time of Peace)