Switzerland's most important public art collection and the oldest publicly owned museum in the world. The main building, a monumental 1936 block just south of the old town, houses works spanning from the 15th century to the 20th: Lucas Cranach, Hans Holbein, Rembrandt, Cézanne, van Gogh, Picasso, and a remarkable group of German Expressionists. The collection's depth in Swiss painting — particularly Arnold Böcklin — is exceptional.
The new wing across the road, connected by an underground passage, hosts major temporary exhibitions and more recent acquisitions. If you have time for only one museum in Basel, this is it. The building closes on Mondays; the combined ticket for both wings is worth getting.