Margarete Bottiger, who earned her living as a housemaid, lived in this tower from 1927 until her death in 1993, and the rooms—one to a floor, connected by ladderlike stairways—are just as she left them, filled with worn furniture, knickknacks, old appliances, and household products from long-ago decades. Ms. Bottiger shared her quarters with an unhealthful number of cats, who had access to the top-floor kitchen via a ladder from the adjacent town wall.