The Fridericianum is the city's most important art building — a late-18th-century neoclassical pile on the Friedrichsplatz, originally built to house the elector's curiosity collection and library. Since 1955 it has been the central venue of the documenta, the world's most important exhibition of contemporary art, held in Kassel every five years.
Between documenta years the Fridericianum runs ambitious solo and thematic exhibitions of leading contemporary artists. Even with nothing on, the square in front of it is one of the great urban spaces in central Germany. Combine a visit with a walk around the surrounding documenta sites — many works from past editions remain scattered throughout the city.