A flooded Mexican cave that hides a river beneath the water.

This incredible college library is a visual masterpiece of mosaic art. It also looks kind of like a giant boombox.

There must be a pun in this haystack somewhere...

The most confusing clock in New York.

Tucked away amidst some of the most famous addresses in the world is New York's only fraction of a street.

The final resting place of the great navigator, or maybe his brother.

Tiny horses tethered to antique rings are scattered around the city.

10,000 flowered plants bloom in the City of Roses.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

Dr Barnes' $25 billion private collection of art and arboretum.

This elaborate towering structure was once famed for its revolutionary height.

Yo, Adrian!

This steep cable railway has been hoisting passengers in the heart of Québec City for over a century.

This lovely, if imposing, piece of Canadian gothic is possibly the most photographed hotel in the world.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

The bat-covered home of one of the world's most popular brands of rum is located on a tropical Art Deco campus.

The ruins of an ancient city built by Mayan traders is centered around a temple of a sacred feathered serpent deity.

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

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

The only castle in North America to ever house European sovereigns.

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

This charming wooden church was disassembled and moved not once but twice before settling in this Prague garden.

Gargoyle head that brings good luck.

A wunderkammer of gold and silver reliquaries and ancient saintly bones.