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

Sparkling, calcite-covered skeletons of children who may have been sacrificed to appease an angry god.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

Elaborate tile work in this railway station tells the story of Portugal.

Ancient catacombs form the foundation for this Rococo orgy of a church.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

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

An exquisite collection of fairytale conveyances that puts most car museums to shame.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

An underground city of salt.

Spend your honeymoon where the Devil had his wedding.

The oldest church in the Estonian capital is home to over 100 fantastical cemetery coats-of-arms.

The Guardian of Tallinn.

A subterranean house of worship carved right out of the bedrock.

The oldest museum in Russia is home to a fascinating collection of nearly two million anthropological artifacts and anatomical curiosities.

This building holds the embalmed remains of the leader of the Bolshevik Revolution.

The tallest stationary dunes on Earth also happen to sing.

Enormous statue of the Emperor of the Mongols.

A natural arch offers panoramic views of Yangshuo's karst hills.

Hidden behind musical flora and forgotten for over a thousand years, this cave is now a neon dream.

This massive neon wheel is the only one of its kind to be built over a bridge.