One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

An abandoned relic of the city's failed experiment with below ground transit.

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

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

An old world fairytale-land with over 350 fairy folk figurines hidden amongst 800 year old cedars.

Where beautiful signs live on forever.

Paris' linguistic guide to the international language of, yes, love.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

Carnivorous plants, medieval aphrodisiacs, and the largest original wood structure glass conservatory in the western hemisphere.

A modernist landscape of water and sci-fi concrete.

A hidden network of subterranean passageways lies tangled beneath Indianapolis' bustling City Market.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

Ruined 11th century abbey built by King David I in Edinburgh, Scotland.

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

Surreal riveted sea forts once protected the Kent shores from German attack.

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

The installation’s official name, “You Who Are Getting Obliterated in the Dancing Swarm of Fireflies,” says it all.

These remote Florida islands have a history of sea turtles and sunken treasures, and one of the world's largest coastal brick fortresses.

A rare view of a preserved Victorian science museum.

A psychedelic labyrinth on the San Francisco bay.

A beautiful geyser under environmental threat.

Pompeii's less famous neighbor is still revealing her secrets.

A hotel and restaurant serving as the mecca of kitsch.

The atmospheric road was never meant to be so creepy.