The Coin House
Visit to the tourist attraction of Sweden - the part of Visby city wall - The Coin House: the northern and eastern wall of the building form an integral part of the city wall, suggesting that the building was present before the wall was constructed.
Wikipedia: Despite its name, there is no evidence that this building ever functioned as a mint. Dendrochronological examinations have shown that the building was built circa 1225, and probably incorporated into the wall in the 1280s. It is aligned diagonally, in relation to the wall. Because of its location, it was difficult to build the wall in front of it. Instead, the building was incorporated into the wall, strengthened and turned into one of the wall towers.