If you can look past the nearby sewer pipes, this urban sinkhole grotto is a mini-paradise.

Found down a long dirt road, a sacred Mexican cenote and 18th-century hacienda remain hidden.

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

This one-of-a-kind convent boasts a kaleidoscopic exterior of stars and double-headed eagles.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

Its sunny hues are believed to have inspired the town's color palette.

Iconic red and white plaques show the creative names invented to navigate the city streets.

A sprawling network of century-old subterranean catacombs lies beneath a nondescript suburban home.

A spooky juxtaposition of caves and graves gives this legend-filled cemetery a particularly haunting vibe.

The sixth of London's "Magnificent Seven" cemeteries, and a source of unlikely inspiration to Beatrix Potter.

A Victorian park cemetery, standing on the site of what was once the Great North Wood.

A hidden gem in the middle of the city's infamous Jewelry Quarter.

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

This medieval sanctuary's tree-framed door looks like a portal to a mythical realm.

This silent sentry in the crypt below a large Gothic cathedral is often knee-deep in water.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."