Gladiators once walked this ancient, subterranean passage.

Where commuters walk through remnants of an ancient Greek necropolis.

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

Preserved portions of Athens's ancient defenses are on display in a subterranean parking garage.

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

This Ottoman-era Greek Orthodox Church was built to honor Agia Pareskevi, a Christian saint.

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

Underneath one of the region's most historic roads lies the home of Plato's successor.

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

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

An ancient Greek monument and a Byzantine church coexist inside this cave.

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

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

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

View the ancient remains of buildings and the ancient "River of Hades" before hopping on a train.

This unusually-named reservoir found a second life as a nature preserve.

A small stone monument marks the spot on Stavely Road where the first of hundreds of missiles touched down during World War II.

It is against the law to obstruct the view from the top of this English burial mound.

This small, round building is the entrance to a bomb shelter built in anticipation of World War II.

A swirling spectrum of stained glass dazzles visitors who enter this subway station.

Every year, the colorful murals of Montreal get a complete makeover.

Towering high above the neighborhood of La Candelaria, the church is easily recognizable by its distinctive red-and-white striped facade.

This tiny shop has been serving traditional tamales for more than 200 years.

A celebration of Colombia’s premier contemporary artist.