The massive Emperor's Tower, completed in 1522, with walls up to 4.5 m thick, stands on the highest point of the rock. The interior is arranged round a huge central pillar, encircled by a vaulted gallery, whose design can be clearly seen from the second floor, at the start of the tour. On the third floor, thirteen cells are reminders of various prisoners jailed at Kufstein, mainly when the castle was a state prison from 1814 to 1867.