Nevada's largest cactus collection stands outside a candy mogul's small factory.

This subterranean passage reveals the city's mining history as well as its legendary terrors.

One of the longest water bridges in the world was built over a supposedly haunted swamp in Louisiana.

Shop for books in the New Orleans house where William Faulkner once lived.

One part local history, 99 parts gruesome haunted house.

Spend your honeymoon where the Devil had his wedding.

This stately mansion, built in 1787 by America's first Secretary of the Navy, is rumored to be one of the most haunted buildings in Washington, DC.

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

An Aztec snake god has taken the material form of an apartment complex.

Legend has it thieves once stashed their treasures in this crater in the Mexican desert.

A geological mystery on Camelback Mountain.

One of the world’s largest cave systems houses legends, concerts, and wondrous rock formations alike.

Limestone caves with spectacular showcase chambers.

Man-made mineral caves house massive bat colony.

These numerous Israeli caves were dug out over hundreds years for reasons ranging from hideouts to burial sites.

Discovered after draining a local pond, these ancient man-made caves are still a complete mystery.

An extraordinary "City of Caves" carved from solid stone.

These ancient sea caves hold Britain's highest concentration of Pictish rock carvings.

A galaxy of glowworms—larvae of a gnat—hides deep in the belly of these caves.

Human-made caves excavated to hide a secret society of wealthy pagans.

A wonder of natural limestone formations etched by millions of years of natural interaction between rainfall and rock and air.

A gothic palace of endless stalagmites and pseudoscorpions waits within one of the world's most beautiful caves.

These Great Lakes sea caves accessible by boat in the summer turn into temples of ice reachable by foot in the winter.

Rare recess caves fill this unbelievably beautiful Ohio park.