This pre-Revolutionary War grist mill ground corn and flour for soldiers in seven American wars.

The ghostly remains of an accidental sea.

The decaying adobe remains of an old homestead are just off the beaten path in Joshua Tree National Park.

A regular looking rock with an unbelievable history.

Hike amid the palm trees that thrive among Southern California's Indio Hills.

The attic and basement house two museums stuffed with oddities like swallowed spoon handles and a shrunken head.

The drama of nature in full effect in this Nevada State Park.

These layered sandstone mountains in China look like they are made of pressed crayons.

Intensely colorful calcite pools in Southern China.

Hidden in a grotto 26 feet below Nottingham's oldest hotel, this stylish subterranean drinking den is notoriously hard to find.

There's a labyrinth of medieval chambers hidden deep below a 15th-century pub.

An engineering error ensured this cavernous 350-foot-long subterranean thoroughfare was never used as intended.

This rustic cabin, outfitted with gun slits, was once home to John D. Tewksbury, patriarch of the bloodiest family feud in American history.

This geothermal hot spring hides beneath a slowly growing mineral dome.

Dramatic river bend surrounds a natural red-rocked pedestal.

Giant pinnacles in the sun-scorched lands of Southern Utah have been nicknamed "white ghosts."

One of the American Southwest's most extensive collections of Navajo rock art.

Nearly 300,000 acres of wildlife, natural splendor, and a hidden ghost town have been designated a national monument.

Bizarre lunar-like landscape with thousands of large stone "hoodoos."

A striking, menacing sandstone peak towering above a landscape that's equal parts Mordor and the Moon.

On Hilton Head Island this bronze King of the Sea rules all things briny—and lets you know if you’re late for lunch.

Where a rare geological phenomenon created a section of rock that resembles a checkerboard.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

An abandoned quicksilver mining town surrounded by the Big Bend parks.