Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

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

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

A museum within a museum, devoted to history's most questionable medical devices.

Modern technology and live displays tell the story of the Pacific during WWII for the Internet generation.

This peaceful Massachusetts graveyard was one of the first "garden-style" cemeteries in America.

This mysterious and once-grand memorial still embodies a remarkable architectural vision.

New Orleans' famous cemetery, located on the site of a former race track.

These tombs were built into the side of a mountain so that ancient angels could reach the dead.

One of only two remaining Victorian-era greenhouses in New York.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

Mosaics, storks, and brothels—this ancient city has it all.

A castle built for love, and abandoned due to heartbreak.

Buildings that dynamite couldn't bring down were abandoned because of bathroom issues.

The summer home of the largest colony of bats in the world.

Dedicated to improving the plight of the rare scaly anteater.

Breathtakingly blue walls shimmer inside the "Glacier Behind the Town."

A museum designed by and dedicated to P.T. Barnum in the town where he is buried.

Julia Morgan's Moorish-Gothic labyrinth of fountains, trees, natural light and Oakland's notable dead.

Abandoned cemetery of the former Psychiatric Hospital of Volterra.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

Pompeii's less famous neighbor is still revealing her secrets.

This 16th-century monastery has been turned into a surrealist architecture compound.

A 250-year-old timepiece-automaton adorned with golden mechanical birds, which still sing to this day.