This "volcanic all-day restaurant" is right on the beach.

These ruins of a sacred Ancient Greek temple stand next to a luxurious modern resort.

The spiral staircase hidden inside this giant Parisian column was likely built for Catherine de Medici's astrologer.

A well-preserved medieval village nested on a rocky outcrop and surrounded by a network of cliffs, natural bridges and canyons.

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

A medieval military street hidden beneath a charming French fishing village.

An aluminum skeleton brings Chinese mythology to the French shore.

Ivy-covered Medieval tunnels cut through this charming town in France's Loire Valley.

Do these monsters look familiar? The gargoyles on this church are all from pop culture.

Beggars were miraculously "cured" of their fake ailments when they returned home to this 17th century Paris slum each night.

Abbey built on the ruins of Roman catacombs.

The largest underground lake in Europe.

An 11th-century fortress home to one of the most influential royal houses in medieval Europe.

A tower-like theater in the Swiss Alps built to withstand the high winds and avalanches of the mountain pass.

Florentine Renaissance style building in Switzerland, home to the world's largest taxidermy Great White Shark.

This eclectic architectural gem played witness to Zurich’s colonial past.

The oldest surviving wooden bridge over Rhine lets travelers cross easily from Switzerland to Liechtensten.

These sea caves are the source of Xigia Beach's distinct aroma.

A preserved portion of an ancient Athens barrier is displayed in a hotel basement.

This historic structure has been used as a mosque, a barracks, a prison, a school, and a bakery.

BDSM, 1930s Style.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

A French valley with forests so lush it was nicknamed "the Small Amazonia of the Pyrenees."

Hidden away in a modern library are the remains of one of the 18th century's most celebrated wunderkammers.