Shikoku’s deep south might not seem like the obvious location for a luxury spa resort, given the easy access of hot springs in Hakone and Karuizawa. But Muroto, on the southern tip of Japan’s most rural island, houses a structure that takes the concept to luxurious new heights. The curvy lines of Utuco Auberge & Spa mimic the waves crashing against the volcanic rocks at its front, but the water in its pools has a far deeper source, some 1,200 feet below. Designed by world-renowned make-up range creator Shu Uemura, Utoco’s rejuvenating powers aren’t limited to its own pools and treatments, either.