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

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

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

This symbolic piece of New Orleans architecture is also home to a few ghastly stories.

Take a drunken tour inside the world's largest known geode.

This frequently-photographed waterfall takes only a short hike to visit.

An abandoned facility that has become a place of ritualistic satanic worship, or so rumor has it.

One of only two commuter aerial tramways in the United States.

Hollowed out cedar log tubs set in an ancient towering forest.

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

A beautiful geyser under environmental threat.

This abandoned amusement park was built on a site with a dark history.

The inspiration for H.P. Lovecraft's horror stories and Batman's Arkham Asylum is now a condominium complex.

The first declared National Monument in the United States.

Read a book next to a Midtown waterfall.

Where America's first doomsday cult awaited the end of the world.

Mysterious rocks that ring musically when struck.

Home of an evil witch famous within southern folklore.

Hellam Township is reputed to feature seven remote gates, which when passed through in the right order, open an entrance to hell.

A museum and shop on Bourbon Street located in the former home of the second Voodoo Queen of New Orleans.

This New Orleans tree is filled with hidden chimes that produce a carefully tuned melody.

Enormous lake at the bottom of a unique cave system.

The final resting place of New Orleans' most famous voodoo priestess.

For two weeks every June, fireflies in the Smoky Mountains perform an astonishing light show.