This 15th-century island fortress later served as home to the executioners no one wanted to live near.

This church combines Christian, Byzantine, and ancient Greek architectural elements.

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

These caves secretly held national treasures during World War II.

This Ottoman-era church is hidden amid a busy tourist area.

Legend says this sacred tree was a gift from goddess Athena.

This small museum once served as a royal hunting pavilion for King Otto Friedrich Ludwig.

A tiny Greek Orthodox church from the Ottoman era hides on a busy city street.

This small chapel holds the mummified heart of one of the heroes of the Greek Revolution.

A man's head is enshrined beneath a statue near the first building constructed for the modern Olympic Games.

A crushed gate and giant bronze head serve as a reminder of Greece's fight for freedom.

The oldest standing Byzantine church in Athens is tucked within a monastery in the middle of an upscale shopping district.

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

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

A grotesque collection of wax limbs depicting the symptoms of venereal disease.

Stalactites and stalagmites in a beautifully lit cave.

This elaborate hole in the ground was built as a sacred site for an ancient civilization.

Ancient cave tombs known as the "houses of fairies."

A resort destroyed by a mysterious bombing offers visitors only its remains and the riddle behind it's demise.

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

Windblown rock formations in an ancient Roman quarry.

Crushed coral and crystals give the sand its signature coloration.