These caves secretly held national treasures during World War II.

An often overlooked ancient site in downtown Athens with substantial history (and nature).

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

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

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

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

A gorgeous mural outside a beloved D.C. restaurant pays homage to famous Black Americans.

How did an Australian statue of the Bard of Avon end up in the Hungarian capital?

One of the newest mosques in a city filled with thousands.

This arch granting triumphal entrance into Antalya was designed to honor the emperor's visit.

The ancient latrines of the Greeks, in all their public glory.

The only residents of this abandoned housing development full of identical castles are stray cats and dogs.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

This famous city eluded concrete detection until the early 2000's.

This seemingly out-of-place gas station by the Watergate hotel was once described as the most expensive gas station in the world.

A plaque marks the spot where the saint was shoved off the Charles Bridge and into the river.

This Czech church doubles as something of a permanent fashion exhibition for a statue of the Infant Jesus.

A surreal statue honoring Prague's favorite literary son.

A turn of the century building boasting some of the most beautiful art nouveau architecture in Prague.

Increasingly decayed figures stand as a powerful reminder of the human costs of Czech Communism.

Synagogue built from the stones of Solomon's temple contains the golem of Prague.

Despite attempts by local police to discourage it, Beatles-inspired graffiti has been a means for artists to air grievances for decades.

A bust of Franz Kafka spins in pieces, reflecting the writer's inner torment.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.