This natural wonder drops 16 stories straight down through rare flora and streaming waterfalls.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

The ghost town left by the worst nuclear disaster of all time is being taken over by nature and urban explorers.

This strange seaside tower got its name from a wealthy eccentric who would hide coins among its stones.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

The longest continuous lava tube in the continental U.S. offers 2.5 miles of dark explorations for the adventurous.

This knobby, drooping New Orleans oak is a favorite place both for climbing and for meeting giraffes.

A "gravitational anomaly" located in the redwood forests just outside of Santa Cruz, California.

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

An ancient capital city that dates back 3,000 years old and harbors many surprises.

The world's longest known cave system.

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

The atmospheric road was never meant to be so creepy.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A stunning, two-tiered waterfall made famous by poets, artists and the legend of a ghost dog.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

Staves, storm-calling, and of course, necropants.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

A heavenly experience, right here on Terra Firma.

Macabre astrological automaton clock dating to the late 1400s.

One of the world's oldest and most massive living organisms is a grove of quaking aspens.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.