The Silver Cap (Silverhättan in Swedish) is the most recent tower of the city wall of Visby, built by the Teutonic Knights who ruled Gotland between 1398–1408. The name Silver Cap alludes to the earlier silver-coloured shiny roofing, probably made of lead sheet. The tower is also known under the name of Kames which dates back to the 17th century and stems from the Latin word comes, meaning count. 

The tower belongs to the most recently erected group of defensive towers and is situated at the corner between the part of the wall facing the sea and the part facing land. It is supported by two large buttresses. At the top of the tower, on the third floor outside, there used to be a wooden gallery for archers. One can still see the remains of beams which once supported an archers' parapet. On the same floor there was also a place where a fire could be lit, mainly used for signaling purposes. In the beginning of the 18th century during the Great Northern War, the arrowslits were enlarged. It was feared that the Russian military, which had earlier ravaged the eastern coast of the island, would attack Visby. The governor and major general Anders Sparfeldt equipped parts of the city wall, the towers and the gate towers, with firearms.