The Gate can be visited
Town Fortification Nürnberg-Tiergärtnertor

The Tiergärtnertor, a pointed-arch gate, is an element of Nuremberg's city wall, located in proximity to the Kaiserburg. It once served as the main access to the city from the northwest.
History+
The Tiergärtnertor was erected in the late 13th century as part of Nuremberg's penultimate city fortification. Its name derives from a wild animal enclosure of the burgrave in the city moat. Originally, it consisted of a gate tower with a square floor plan and an outer barbican. In 1516, two upper floors with polygonal bay windows were added.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://commons.wikimedia.org/wiki/File:N%C3%BCrnberg_Tierg%C3%A4rtnertor_2.jpg
This description draws on the facts documented in the linked Wikipedia article; Wikipedia content is licensed under CC BY-SA 4.0. Wording and editing: Mobile History.
Location: 49.4576, 11.0742