The tidal island of Mandø, about 15 km southwest of Ribe in the Wadden Sea, is reached by a seven-kilometre road across the mudflats that disappears underwater twice a day at high tide. Visitors usually go on a tractor-pulled bus (the traktorbus) from Vester Vedsted, which only crosses when the tide is right.
The island is tiny — a few square kilometres of polder, around 30 permanent residents, a small church and a single inn (the Mandø Kro) where you can eat. The point is the journey: the surreal flatness of the Wadden Sea, the seals on the sandbars, the wading birds. Bring binoculars and watch the tide tables.