Emil Nolde Stiftung Schleswig-Holstein

By far the biggest and most impressive collection of Emil Nolde’s work is in his architecturally arresting former atelier at Seebüll. The exhibition is worth a half-day's excursion, which is just as well because it's fairly remote – you'll need your own wheels to visit the location, which is almost on the Danish border. There's a suitably arty cafe.