This mystical orb covered in strange symbols is thought to have been used in ancient Greek magical rituals.

This striking sculpture of Icarus honors Greece's fallen flyers.

Scars of this building's past life as a violent prison still cover its walls.

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

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

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

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.

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

Legend says it was constructed with the destroyed pillar of an ancient Greek Temple.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A perfectly preserved example of a fortified Medieval ricetto.

Europe’s oldest natural human mummy.

These delicate sand pyramids look like naturally occurring gothic spires.

This spire on an Austrian mountain is wrapped around a long spiral slide and has the world's tallest wooden observation deck.

The medieval "dragon" on an Austrian city's coat-of-arms comes to life in a fountain.

The costumes depict the Kurent, the star character of the annual Kurentovanje festival.

The world's largest historic armory was established by independent citizens to defend themselves from the wars of larger forces.

The shell of a medieval fortress offers commanding views of the area it once protected.

Fantastic stories on a miniature railroad.

Double spiral staircases are not unheard of, but they are very rare.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

This 14th-century monastery survived Turkish raids, Nazi occupation, and even a stint as a spot to store towels.

A relic from the Industrial Revolution got a second life as a contemporary performing arts space.