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

The only surviving choragic monument is a trophy awarded in 334 BC for the winning dramatic chorus.

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

These caves secretly held national treasures during World War II.

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

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

This gem is often wrongly overshadowed by the larger, newer Metropolis church in Athens.

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

Large collection from the 3rd millennium BCE.

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

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

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

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

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

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

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

This impressive chasm is one of the longest natural underground cavities in the world.

Abandoned 18th century weapons factory in the Aezkoa Valley.

Ancient paintings known as the "Sistine Chapel of Cave Art."

This French ghost town from World War II has been left as a memorial to German atrocities during World War II.

Exquisite examples prehistoric bas-relief carvings.

A quarry cum sculpture park where the works of art are chiseled into the very walls.

The medieval "Bearded Man" relief still serves as a clever flood warning marker.

This house covered in small stones was the work of one man over the course of nearly 30 years.