The Ottomans, the Japanese, the ancient Greeks, Roman emperors and hardy Finns, across the world and across the centuries, dipping oneself in curative waters has always been popular. And anyone who has spent a relaxing day enjoying massages, treatments, saunas, and hot springs can tell you there is one good reason for that—spas are rejuvenating.

Where Belgians once drank the iron-laced water in the little town of Spa, modern vacationers indulge in medical spas. Overseen by a health professional they treat their ailments with a variety of traditional and alternative therapies. Roman spas had full gymnasium complexes. Today club spas help guests improve their fitness. For hundreds of years Japanese have visited traditional ryokan or inns near hot springs. Modern travelers check in to resort spas to be enveloped in relaxation and luxury. For those pressed for time, there are day spas. Take your pick. They're all wonderful.