The first hospital in the New World.

An eccentric German artist built this weird and wondrous castle packed with shocking sculptures and alien art.

Hundreds of pieces of ancient Taíno art cover the walls of this Caribbean cave system.

Renowned restaurant tucked in a cave once occupied by buccaneers.

This trio of Dominican cave lakes comprise a colorful biosphere of natural life.

Rare karst landscape eroded from a flat seabed.

A Romanesque tower appears when water levels drop.

Blue-green pools and smooth stones comprise one of Spain’s most idyllic hidden wonders.

An exact replica of a colossal Olmec head sits atop a pyramid within a Madrid traffic circle.

Moorish signal station on a stratgic rocky outcrop.

This quaint Spanish village agreed to be painted blue as a marketing stunt but found that they preferred it that way.

Abandoned Nazi train station turned underground astroparticle laboratory.

The former 1920s mansion of a prominent Catalan developer was used as the Soviet Embassy during the Spanish Civil War, and there is still a bunker below the garden.

A 16th-century Andalusian palace.

One of the most spectacular bridges in Spain spans a narrow chasm that divides the city of Ronda.

Volcanic rocks ground down into sand make this Spanish beach as black as night.

This former charity hospital for elderly clergy houses some of Seville’s most treasured paintings.

Of course Salvador Dalí lived in a castle...

A science fiction-inspired apartment building designed by a famous Spanish architect.

Cliffside houses provide a spectacular view from their perch above the valley.

Its appearance in "Game of Thrones" may spur on the long-awaited restoration of this medieval shipyard.

Occupied for six centuries by Franciscan Order nuns, this monastery is an amazing ode to Catalán Gothic architecture.

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.

This magical space partly designed by Antoni Gaudi is one of the best examples of romantic gardening in the Mediterranean.