A once grand hotel now sits eerily abandoned in the Catalan countryside outside Barcelona.

Turntable anonymously received orphans, alms, and groceries.

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

Grandpa Rainbow felt the neighborhood needed some color, so he picked up a paintbrush and went to work.

A series of modernist treehouse hotel rooms grace the outskirts of an Arctic forest.

A sculpture of a giant hand reaches for the stars in the middle of the Atacama desert.

One of Chile's most active volcanoes is riddled with beautiful caves.

This odd Chilean waterfall-cano hotel must be entered via a rope bridge.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.

A submerged village appears when dam levels drop.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

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

Countless stories attempt to explain Poland's mysterious J-shaped trees.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

This scalding hot river was thought to be a myth until one geoscientist made it his quest to study the mystical waters.

The mortal remains of an estimated 70,000 people lie in the basement of a monastery in Lima, Peru.

A remote candy-striped mountain in the Peruvian Andes straight out of the pages of Dr. Seuss.

Keshwa chaca, among the last handwoven Incan bridges, crosses Apurimac Canyon in Peru.

A solitary tree has grown up all alone on Lake Wānaka, backdropped by the beautiful Southern Alps.

A perfect turquoise lake colored with glacier dust.

Some of the clearest water anywhere in the world.

This electric green sulphur lake in New Zealand looks like a cartoonish radioactive dump site.

The Dalai Lama named this New Zealand landscape the "Spiritual Center of the Universe."

Tubing through a cave lit with glowworms is a magical underground experience.