This historic "City of the Dead" lies prominently in the center of New Orleans' famous Garden District.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

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

Tubing through a cave lit with glowworms is a magical underground experience.

The magic's in the hole!

San Francisco's newly reopened hands-on science museum.

A collection of oddities including Dr. Kevorkian's suicide device, the Thanatron.

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

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

Home to items never before seen by the public.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

Northern Ireland's Brobdingnagian stepping stones.

Stepping away from the glitz of mobsters and casinos to learn about the other history of Vegas.

A hand-built folk art installation covered with messages of God's love.

The ghostly remains of an accidental sea.

A snapshot of the city's fascinating voodoo culture.

A heavenly experience, right here on Terra Firma.

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

An abandoned Jazz Age dream home and con man's hideout in Death Valley.

The taxidermy remains of the first mammal ever cloned from an adult cell are on display in Edinburgh.

The oldest licensed distillery in Ireland.

An 1814 castle that hosts an exhibit of "explorabilia".

The oldest pub in Ireland may also be the oldest surviving bar in the entire world.

One of Ireland's most infamous prisons for rebels including men, women and children.