A corkscrew-shaped barn in Ireland.

A modern version of the stone cairns built by the Inuit.

The Pope’s secret escape route.

Abandoned railway line circling the city of Paris.

Small church built in the 19th century for whites and slaves to worship together.

These homes carved into the mountains seem to defy the laws of nature.

An endless sea of white conical domes.

A home made entirely from scrapped, reclaimed and recycled material in Whitman County, Washington.

One family's environment-friendly hobbit-house in Wales.

Massive fortified towers blend North American and Chinese architecture.

Rock-cut cave complex filled with ancient Buddhist artwork.

A tunnel dug through the side of a mountain by hand provides convenient yet death-defying access to a small village in China.

Amazing and mysterious Neolithic settlement on Scotland's Orkney Islands.

Bring your hiking shoes, wool socks, and thermal underwear for a stay in these cozy forest huts.

The home of a deceased Hungarian artist is now on display for visitors.

Three bridges straddle a stream, one stacked upon the other.

The pretty iron lamp is a reminder of the architecture underneath London's streets.

This enchanting rainforest hotel looks as though it grew from the forest itself.

A father built this one-of-a-kind house in the shape of his son's race car.

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

One of the world's most complete mineralogical collections.

This Japanese-inspired labyrinth of hot springs is hidden in a Chilean forest.

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

The ruins of a grand theater destroyed during the most powerful seismic catastrophe ever recorded.