We have been eagerly anticipating this since a teaser went out last spring—and finally, the THANN Sanctuary Spa has opened at the Castle Hotel & Spa in Tarrytown (800-616-4487; thannsanctuaryspany.com). Known throughout Asia, this is the first THANN spa in the United States. The spa’s massage therapists spent six weeks in Thailand last summer learning massage techniques, THANN-style. The 8,700-square-foot spa has seven treatment rooms, a VIP treatment suite with its own deep tub and private outdoor gazebo, separate locker facilities, relaxation lounges, and steam rooms for men and women.