View larger size Hay Barn The Hay Barn, featuring rubblestone walls, is located to the east of the Marstall. It was also originally built to help defend the city against attackers. In the Middle Ages, a tower stood here at the north-western corner bastion, known variously as the Coat Tower or the Women’s Tower. After it was destroyed in 1693, the present building with Baroque partial hip roof was built. Until 1824 it was used to keep hay for the horses kept at the neighboring Marstall, then it served as a muncipal storehouse. In 1963-65, university lecture halls were built inside the Hay Barn.