After this medieval Serbian fresco was hidden for centuries, an image of it became one of the first to be sent into space.

A war-torn Olympic relic is being overtaken by graffiti and nature.

A deadly ancient portal to the underworld.

Strange rumors surround the artist who created these solemn metal guard dogs.

A unique two-level bridge designed to honor a king.

The remains of a sunken military ship wreck visible through clear water.

A collection of intricate sculptures so small they have to be seen through a microscope.

Sitting beneath an unremarkable residential building is a museum devoted to classic Pinball.

"World machine" built by an untrained Austrian farmer.

Everyday, fans from across the globe visit the statue of one of the greatest Formula One drivers in history.

The largest Canadian war cemetery in Italy commemorates those who died in one of the bloodiest battles of the Italian campaign during World War II.

This network of roads is one of the most unique Etruscan creations ever discovered.

Next to the Leaning Tower of Pisa is a cemetery home to ancient sarcophagi and disturbing murals.

A space dedicated to contemporary art and culture, co-chaired by fashion icon Miuccia Prada.

Legend says this mysterious stone head belongs to a woman who was petrified by an alchemist.

A 12th century church completely covered in shells.

An eerie collection of the surviving structures from a past celebration of the future.

Famed architect Antoni Gaudi built this generous thank you gift to a friendly host who housed him during a job.

One of the most spectacular bridges in Spain spans a narrow chasm that divides the city of Ronda.

Earth's rocky history has rarely glittered so brightly as it does in this Spanish museum.

The world's largest wooden structure.

There's an exclusive Beefeaters pub hidden in the Tower of London.

One of Scotland's most important modern structures, it just made the '100 Most Endangered Sites' list.

Ruined castle with subterranean vaulted Goblin Ha' or "Goblin Hall."