France's most famous cemetery, with some of its most curious tombs.

An intricate network of underground tombs carved into volcanic rock.

This "volcanic all-day restaurant" is right on the beach.

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

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

Where commuters walk through remnants of an ancient Greek necropolis.

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

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.

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

Beneath the southern end of the Golden Gate Bridge is the “Gibraltar of the West Coast,” a fort built to protect the San Francisco Bay from naval attack.

This lighthouse has been guiding shipping into the Golden Gate since before the American Civil War.

Ride on a fully-restored Nike nuclear-tipped missile elevator from the Cold War.

Concrete strongholds stand guard over the Golden Gate.

Dive bar built out of the remains of a whaling ship.

Take shelter from Hawai'i's tropical heat under the massive canopy of largest Banyan tree on the island.

A series of waterfalls and pools that flow through the 'Ohe'o Gulch and into the ocean.

This unusual lava tube spouts seawater during high surf.

A controversial memorial at the place where Captain Cook met his violent end.

Longest fortress system anywhere in Europe.

The oldest arboretum on the Dalmatian coast doubles as the gardens of Kings Landing in "Game of Thrones."

American artist J. Alden Weir purchased this 60-acre estate for $10 and a painting.

After the comedian dissed a Connecticut town on his show, they named a sewage treatment plant after him.

After decades of neglect, a brutalist icon is getting new life as an eco-friendly hotel.