The Gate can be visited
Town Fortification Jülich-Aachener Gate

The Aachener Tor in Jülich is a remnant of the early modern city fortifications. It was designed as the main western access point.
History+
Construction of the Aachener Tor reportedly began around 1548, after a city fire impacted Jülich in 1547, necessitating new fortifications. Architect Alessandro Pasqualini was responsible for the city's design and its defensive structures. A stone tablet above the archway, which existed until 1798, named Duke Wilhelm V of Jülich-Kleve-Berg as the builder and dated its construction to 1548. Recent excavations suggest that the gate originally aligned with the older Hexenturm. It was only around 1648, during Spanish rule, that the gate was moved to its current location, possibly as a new construction, with the old builder's tablet being reused.
Source: Wikipedia · Licence: CC BY-SA 4.0 · Image: http://de.wikipedia.org/wiki/Datei:Aachener-Tor.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: 50.9193, 6.3585