Arroyo Tapiado Mud Caves

It sounds like a spa you'd go to beautify your skin but the caves are actually named for gypsiferous claystone, also known as mudstone. The walls and ground are made of dried mud formed over 5 million years and then eroded subsequently by water drainage. Although the caves are generally safe, it's been advised that visitors should not go after rainy weather as the soft walls of the caves can collapse. A 4WD car is also recommended if you plan to drive through the canyon where the caves are located. (Photo by Brian M. Good)