Just a few steps down can transport you into a completely different world: This neo-baroque park from the early 19th century is situated 26 feet below the level of the surrounding streets. Dense ivy covers the orangery-turned-gallery for contemporary art. Running streams meander through the symmetrical gardens, and round-faced cherubs sit astride crocodiles. In the summer, jazz and other concerts breathe life into what was once a refuge for nature lover Franz Körner.