In the Hall of the Mountain King

As if the idyllic, 1,800-m-high Swiss hamlet of Arosa wasn't already alluring enough, the addition of a sprawling $28 million spa makes it irresistible. Bergoase is the latest work of homegrown architect Mario Botta, whose commissions have included San Francisco's Museum of Modern Art and Milan's new-look La Scala opera house. The spa features sail-like steel-and-glass skylights, pictured, employs granite in abundance and is attached by a dramatic glass bridge to the recently renovated Tschuggen Grand Hotel . "I wanted the structure to have a deep, instant and intense bond with its surroundings," Botta says of the native...