A Romanesque tower appears when water levels drop.

Religious dwelling in a Spanish volcano.

Village situated on a narrow volcanic escarpment.

A striped 12th-century basilica sits in the countryside of Sardinia.

Recognized the world over as the home of the McCallisters in the 1990 movie "Home Alone."

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

This medieval hilltop village was abandoned at the end of the 19th century, after existing for more than 500 years.

One of the few remaining casualties of the London Blitz, this destroyed church has become an enchanting public garden.

The “Sistine Chapel” of the Middle Ages merges 11th-century science and religion in wondrous hues.

A star-shaped fortress town fort built in the geometric model of the Renaissance utopian city.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

This eye-popping Icelandic crater lake is surrounded by red volcanic rock.

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

Constructed during the 7th century this is one of the oldest largely intact Christian churches in England.

This statue dedicated to the story of a Flemish boy and his dog was relatively obscure in Belgium, but a cult sensation in Japan.

This quaint Italian town keeps losing ground as the sides of its plateau slowly erode.

This centuries-old Italian chapel hangs midway down a sheer cliffside.

Sleep in a glass pod dangling off a cliff.

This open-air mosaic gallery honoring an English artist took hundreds of volunteers more than seven years to create.

The sound of swaying stalks in this stunning grove has been named a governmentally recognized sound.

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

A gravity-defying "devil's bridge" that has a surprising architectural feature for its stability.

The interior of this Serbian royal family's mausoleum is covered with exquisite mosaics.

A public urinal so pretty, it was declared a national monument.