There are many Byzantine-era churches still standing in Athens, but this is the only one with a 2,500-year-old column rising through its roof.

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

The ruined doorway is a portal to the building's turbulent and torturous past.

An ancient octagonal weather station named for the eight Greek gods of wind.

Where commuters walk through remnants of an ancient Greek necropolis.

This small 16th-century church in Athens is almost entirely surrounded by a modern building.

Large collection from the 3rd millennium BCE.

The ruins of an ancient Roman tomb hidden in the basement of a trendy clothing store.

150 or so scrounged-up lamps, chandeliers, and lanterns light up this alley in central Athens.

The Cycladic architecture makes this Athens neighborhood feel like an island paradise hidden in the shadow of the Acropolis.

This graffitied 19th-century building was a prototype of European industrial architecture.

A Byzantine-era church hidden in a wooded area below the Acropolis.

The oldest cemetery of modern-day Athens blends the modern and ancient worlds.

A Byzantine church containing the holy remnants of three saints sits atop the site of an ancient temple.

Hideout of thieves, monks, and goat-footed gods.

A 16th-century Andalusian palace.

The final resting place of the great navigator, or maybe his brother.

This former charity hospital for elderly clergy houses some of Seville’s most treasured paintings.

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

Sitting on an Italian hilltop is this surreal fortress built by the mad inventor of electrohomeopathy.

This garden houses the remains of the ancient Greek port of Marseille.

This historic island prison holds one of the dungeons from the Count of Monte Cristo even though it is a work of fiction.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

An architect transformed this abandoned cement factory into his castle-like workshop.