The Black Tower is a medieval tower in Brussels, Belgium. It is one of the best conserved remains of the first fortifications of Brussels, built at the start of the 13th century. It is located behind St. Catherine's Church on Rue de la Vierge Noire/Zwarte Maagdstraat. This site is served by the metro stations Sainte-Catherine/Sint-Katelijne and De Brouckère on lines 1 and 5 of the Brussels metro.
The Black Tower is notable for being one single medieval tower surrounded by modern-day buildings. This odd sight has made it a popular tourist destination.
Wikipedia https://en.wikipedia.org/wiki/Black_Tower_(Brussels)
Coordinates 50°51'2.885" N 4°20'59.333" E