Alsik Hotel & Spa

The Henning Larsen tower rising above Sønderborg's old industrial harbor is hard to miss, and that's somewhat the point. This waterfront hotel has 190 rooms angled toward Alssund fjord, a 64-meter observation deck open to the public, and a spa spread across four floors, which is the kind of scale that happens when a pension fund and a family foundation decide a town of 30,000 needs a landmark. The Michelin Guide includes it in its hotel selection.