This tiny church near Sleepy Hollow contains Henri Matisse's last work, a rose window, and nine windows by Marc Chagall.

More than five miles of underground passageways.

This large cave is a summer home to thousands of bats and has a rich history dating back to prehistoric times.

This head-spinningly bizarre Depression-era art cave is wall-to-wall quartz and Jesus.

Hiding behind a grocery store is a spectacular cavern carved as part of an old limestone quarry.

Mile-long cave system near Great Smoky Mountains.

Enormous lake at the bottom of a unique cave system.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

The haunting "Hell House Altar" is one of the few remnants of an abandoned college that has been a magnet for local legends.

This tiny alleyway is now a shrine to a subculture riot between the mods and rockers.

The tragic heiress Barbara Woolworth Hutton built her seventh husband this Japanese-inspired palace in Mexico.

A small house sits between two huge rocks, with its back to the sea.

What started as a way to address damp basement walls turned into a house filled with intricate hand-carved designs.

An unusual library of dead things at the Rhode Island School of Design.

Books bound in human skin and H. P. Lovecraft's letters are among a few of the treasures this library has to offer.

A simple Colonial home with a past haunted by death and madness.

An architectural statement of artistic intent smack in the middle of Providence, Rhode Island's Colonial uniformity.

Last residence of H.P. Lovecraft featured in his story "The Haunter of the Dark."

An acoustic anomaly with a mysterious cause.

Explore the wide world of desert plants at this unique Palm Springs botanical garden.

A fiery crater has been burning in the Karakum Desert since 1971.

A crumbling hospital from the 1850s on Roosevelt Island.

A sculpture of a giant hand reaches for the stars in the middle of the Atacama desert.

A new sculpture calls attention to climate change in the centuries-old city it threatens.