The university botanical garden was founded in 1698 and is one of the older such gardens in Germany. It occupies a calm, slightly sunken site below the old town, with palm houses, a Victorian-style fern house, and the usual systematic beds of European flora.
It is a quiet, free escape from the city — open every day, well-tended, and rarely crowded. The greenhouses are warm in winter and a useful detour if the weather is bad.