The highest bridge in America was built for an almost unnervingly small amount of money.

Rustic natural hot springs in the deciduous rain forest.

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

The highest peak in Utah is the hardest to reach, but only if explorers choose the hard way.

Hundreds of drawings left by the land's previous inhabitants remain mysterious.

These old stone ruins in the Oregon wilderness were once bathrooms and are steeped in legends of murder.

On the Oregon coast there is a natural hole that seems to be draining the sea.

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

The world's only international cryptozoology museum is host to an unrivaled collection of mysterious objects.

France's most famous cemetery, with some of its most curious tombs.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

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

Rising from the sea like a stone monster.

This whimsical castle of grottoes was the labor of love of a French postman, and one of the greatest achievements of outsider architecture.

Home of an evil witch famous within southern folklore.

Left untouched since a double murder-suicide in the 1960s, Los Feliz murder mansion remains a neighborhood mystery.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Northern Ireland's Brobdingnagian stepping stones.

Monasteries on rock pillars, once accessible only by frayed ropes.

Under the right circumstances, this waterfall in Yosemite briefly turns a luminescent fiery orange.

The seamy, underground secrets of Portland's criminal past.

A walk through the historic city center, under the streets of Seattle.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.