Pamukkale has mineral springs that have been in use for thousands of years. Calcium rich waters spilling from a hilltop spring are responsible for creating white stone basins. The "cotton castle's" terraced basins hold in the 102 degree F water, and, up until the 90's you could just walk up and jump in. No more. Hotel development and irresponsible tourism around the springs choked the water source and the basins reverted to a dry, dingy, gray. Now, their luster has returned, but you can only walk on carefully laid out paths around the site.