High atop a Mexican rainforest mountain, this ancient pyramid once drew pilgrims countries away.

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

The winter home of millions of migrating monarch butterflies.

Diego Rivera's massive tiled fountain and failed infrastructure project.

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

Twelve natural mummies are displayed in the crypt of this former monastery school.

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

A disquieting Aztec sculpture displays hundreds of stone skulls representing the victims of human sacrifice.

The famous artist couple lived and worked here, in two different houses connected by a bridge.

66,000 pieces of art, donated by one of the world's richest men.

Frida Kahlo's childhood home, now a museum of her life and works.

Part bookstore, part café, and part forest.

This small uninhabited island offers Galapagos-like biodiversity.

An ancient city hidden in the heart of the Sierra Nevada mountains.

This lake’s emerald green waters are a spectacular sight, but it’s not a great place for a swim.

A desert that evokes the surreal.

This red lake 4,000 meters above sea level is home to rare flamingos.

On the outskirts of a desert trading village high on the Andean plain, steel giants have been destroyed by salt winds.

Popular tourist destination where witches in dark hats sell dried llama fetuses for good luck.

A seemingly endless landscape of pure salt stretches far across Bolivia.

A devastated ruin in the south of Belize where British explorers claimed to unearth the Mitchell-Hedges Crystal Skull.

One of the world’s largest suspended aquariums, located in Dubai Mall.

This enormous sports car themed amusement park is home to the world’s fastest roller coaster.

Planned as the world’s first zero-carbon city, it had lofty ideals—but is only 5 percent completed and aiming for 50 percent carbon-neutral.