Tucked into the Schlosspark, the Museum Art.Plus (previously Museum Biedermann) is a private museum of contemporary art with a focused programme of rotating exhibitions. The building itself, opened in 2009, is a sleek piece of modern architecture that sits surprisingly well against the historic palace next door.
The collection ranges across painting, sculpture and installation, with a particular interest in the play of light and material. Allow an hour for a visit; combine with the palace and the Donauquelle for a full day in town.