These balancing rocks in Utah's Moab Desert formed because wind eroded the lower-down rock layers faster than it eroded the thicker caprock. Because earthquakes can topple these balancing rocks, their presence indicates that an area exhibits tectonic stability.

This strange "basalt stack" balances precariously over the water near Digby, Nova Scotia, in Canada.

This balancing rock formation is one of the Brimham rocks, located on Brimham Moor in North Yorkshire, England. Made of millstone grit, it was carved over time through water and wind erosion. The bottom layer eroded fastest.

This huge sandstone boulder sits atop a rocky outcrop in Garden of the Gods park near Colorado Springs.

Yeager Rock, a 440-ton "glacial erratic" on the Waterville Plateau, Washington, ice-rafted to its present location 13,000 years ago inside the 4,000-foot-thick Cordilleran Glacier. The boulder plunked down when the ice melted.

"Krishna's butterball" is a giant glacial erratic perched on a hillside near Mamallapuram, India.

Zimbabwe's Matobo Hills are composed entirely of granite, which weathers into fantastic shapes, such as these balancing rocks known as Mother and Child Kopje.

This limestone rock formation in Egypt's White Desert is not a true balancing rock. Usually found in desert areas, these so-called mushroom rocks, also known as pedestal rocks, form over thousands of years when wind erosion of an isolated rocky outcrop progresses at a different rate at its bottom than its top.

This glacial erratic in California's Yosemite National Park was transported by a glacier and left precariously balanced near Olmstead Point as the ice melted.