This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

These azure waters were thought to lead to the Mayan Underworld.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

Northern Ireland's Brobdingnagian stepping stones.

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

Thousands of exquisitely carved stone water storage wells, hundreds of stone steps fill this exquisite medieval stepwell.

Beyond being incredibly fun, not much can be said about the Hole with certitude.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

The abandoned Japanese amusement park once loomed as a dystopian Disneyland.

This lab's maddening silence is good for business but bad for sanity.

The first declared National Monument in the United States.

A trash dump made beautiful by nature's power.

A snapshot of the city's fascinating voodoo culture.

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

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

The only structure left with direct ties to the Salem witchcraft trials of 1692.

The largest of London's subterranean rivers and once a mad, bad center of London life.

A battle between nature and architecture in the Cambodian jungle.

An island filled with hundreds of hanging, decomposing, decapitated dolls.

A whimsical and twisted animatronic monster tour beneath the streets of Berlin.

Thousands of well-dressed mummies below a monastery.

Hot springs monkey spa in the middle of Hell's Valley.

A tiny microvalley etched into the side of Knocknarea Mountain hides another world.

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