Jarmers Tower (Jarmers Tårn) is one of the few surviving ruins from Copenhagen’s medieval fortification system and today stands as a monument to the city’s early defensive structures.

Originally, the tower formed part of the fortress that once surrounded Copenhagen, but it was destroyed during the 17th century as cannons and modern warfare rendered the old ramparts obsolete. In the 19th century, sections of the former city wall and the remains of the tower were excavated and preserved as a historical reminder of medieval urban planning and defense. Located at Jarmers Plads, the ruin is integrated into the surrounding cityscape as a visible testament to Copenhagen’s transformation from a fortified town to a modern capital.