The start of the big-spa era may have been the refit of 135-meter Savarona by designer Don Starkey in 1991–1992. "It was a 1931 vintage yacht with so much space we put in a large plunge pool, showers, sauna and steam room, and because it was a Turkish yacht, we put in a Turkish bath," called a hammam.

The first spas came from the Mesopotamian area, where ancient Greeks and Romans started using hot springs and thermal baths to treat their wounded soldiers. The word "spa" itself is probably derived from the Latin espa, meaning fountain, or spagere, meaning bubble up, sprinkle or moisten.

Now there are myriad spa techniques growing in popularity, from seaweed wraps to Swedish massage, from salt glow (oil and salt from the Dead Sea) to hot stone therapy (smooth stones harvested from river bed). They are designed to help revitalize the body and restore energy.