An intricate network of underground tombs carved into volcanic rock.

This black sand beach was crafted from volcanic explosions including the historic Minoan eruption.

A quirky bookstore hidden beneath a sea of whitewashed Greek villas.

Replicas of Apollo's leonine stone guard cats still line a sacred row in Greece.

Giant marble phalluses on the sacred island of antiquity.

Gladiators once walked this ancient, subterranean passage.

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

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

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

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

Miles of man-made caves and tunnels are currently used for cultivating mushrooms.

Five candy-colored villages on the Italian Riviera.

Romania's triumphal arch looks out over Bucharest.

This once-derelict building is now one of the most beautiful bookstores in the world.

This memorial to the victims of the Romanian Revolution of 1989 is often compared to a potato on a skewer.

This unique building in the main square stands out among the city's typically Baroque architecture.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

One of Malta’s most popular beaches features a seemingly out-of-place statue of the Virgin Mary and baby Jesus.

The fishing boats that moor in this small lagoon enter and leave through a tunnel to the sea.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

This prison on the Maltese island of Gozo is almost 500 years old, and they have the graffiti to prove it.

These clocks tell time in a theological sense.