The abandoned site of the Beatles spiritual awakening and subsequent revolt.

Putrefaction plateaus in Iran, where the dead were sent for decontamination before going to their final resting place.

17th century mosque for Shah Abbas' harem.

Modern-day cave dwellers carve elaborate homes out of volcanic debris.

The palace of the King of Kings, burned by Alexander the Great.

A bloody history is captured in this former prison turned museum.

Monasteries on rock pillars, once accessible only by frayed ropes.

This Armenian monastery was carved out of cliffs and named after the spear used to stab Jesus.

A geological oddity topped with a 2,000-year-old pagan temple.

Unfinished monument to peace between Turkey and Armenia, long divided by a dispute over genocide.

An abused and forgotten metropolis, abandoned for centuries.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

Mausoleum and Holy Seat of Antiochus I of Commagene.

This hunter-gatherer architecture is believed to be the oldest religious complex known.

A sacred lake with thousands of sacred carp and a biblical history.

Villas that once served as playgrounds for the rich now fall away in decay.

Macabre astrological automaton clock dating to the late 1400s.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

The oldest Roman lighthouse still in use.

An accidental trick of light casts the perfect shadow of a pilgrim of the Camino de Santiago against the cathedral wall.

Commonly acknowledged as the only public monument to the Devil himself.

An ancient Egyptian temple in the middle of Madrid, Spain.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

The Cathedral of Salamanca has a number of unusual carvings but none so surprising as a modern astronaut.