The Altstadt is small and walkable. A morning is enough to take in the market square with the Gänseliesel, the Altes Rathaus, the Johanniskirche, and the surviving stretches of the medieval town wall. The afternoon goes to museums — the university's scientific instruments, the ethnological collection, and one of the botanical gardens — and the famous Studentenkarzer. For longer stays, the cemetery walks (Albani, Stadt) and the Planetenweg scale-model solar system through the city are worth the time.