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

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

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.

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

Eons ago, a rushing lava river formed this pristine passage through solid rock.

A small canyon with petroglyphs and a seasonal waterfall, only a short hike from the remnants of old Route 66.

Inside this store, a mysterious statue draws visitors from the world over.

One man has carved a number of natural New Mexico caves into psychedelic sandstone temples.

A crumbling hospital from the 1850s on Roosevelt Island.

An ancient system of freshwater caves filled with animal bones, including that of species long-extinct.

Natural stone arches form a walkable "cathedral" at low tide, then disappear entirely when the water returns.

A battle between nature and architecture in the Cambodian jungle.

Over 2,000 ancient temples dot the Myanmar landscape at the site of this famed archaeological site.

A once grand hotel now sits eerily abandoned in the Catalan countryside outside Barcelona.

Bask in the 19th century grandeur of an eccentric Freemason millionaire's private gardens.

Mountain where Jesus was first tempted by the Devil.

This cemetery features modernist statues as strange as its name.

This semi-secret storybook hedge maze is also the oldest garden in the city.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Stone memorial that's said to predict the death of the pope and the site of the Cadaver Synod.

At least seven hues of blue and turquoise make this freshwater lagoon unique.

Three bridges and one giant canyon make up this fantastic Spanish settlement.