A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

These "anatomical machines" are only one of the many strange items in this Italian crypt.

This curious building hides eclectic details like medieval gargoyles alongside naked angels and Art Nouveau mosaics.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

Architectural monsters are devouring this palace's every door and window.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

Claiming to be the oldest hat store in the world, this historic haberdashery had a hand (and a head) in the creation of the Bowler.

Since 1874, this macabre collection has developed into a museum devoted to Scotland Yard's mementos of dastardly deeds.

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

An ancient Egyptian temple in the middle of Madrid, Spain.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

For one day every month Barcelona's Estació de França transforms into a market for model trains.

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

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

The site of a tragic massacre that spawned a multimedia franchise.

Jesus' footprints and the first catacombs in the world.

An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

Artfully arranged bones of 5,800 Austrians.

Thousands of well-dressed mummies below a monastery.