Sparkling crystals lure visitors into a cave inside The Centerville Salt Room. Though these crystals aren't made of diamonds, amethysts, or Batman's dental grills, they teem with value and subtle beauty. They're composed of finely ground salt particles, whose negative ions help clear congestion through a process called halotherapy. The Centerville facility uses a halogenerator to saturate the air with the therapeutic mineral, which can also ease eczema flare-ups, soothe allergy symptoms, and enliven homemade french fries for adults and children. To further assuage aches and pains, seasoned massage therapists can stroke sore muscles in the cave or a private kneading nook.