The Romanesque Nikolaitor is the only one of the former five city gates that has been preserved. At the exit from Karlsplatz to Bahnhofstraße, right next to the Nikolaikirche, people left the city to the east through this gate. The city gates were closed every evening until 1832. After that, the walls fell victim to the increasing traffic. The Nikolai Gate dates back to around 1170. Martin Luther entered the city at this point in 1498 and asked relatives - the sextons of the Nikolai Church - for accommodation. The relatives were unable to take him in, so he initially earned his living as a currant singer and then found a home with the Cotta family.