Israel/Jordan
What: Mud

The history: For centuries, people have said that Dead Sea mud holds healing properties. In fact, the ritual of trekking to these mud baths to relax and restore is where the idea of the service spa first originated.

The lowdown: The mud local to the Dead Sea contains a high percentage of salt, and thus, a higher level of nourishing minerals. Can't find Dead Sea mud? Other varieties can be beneficial as well. "The common ones in skin care are sulfur, which is excellent for drying out acne; bentonite, which is very deep cleansing and helps to draw toxins out of the skin; and kaolin, which helps to purify the skin," explains King.