This massive library holds what was once the largest book collection in the world.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

Notorious artist squat renovated into legal studios.

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

The vast, legendary catacombs hold secrets much stranger than stacked bones.

This once-forgotten oasis in the middle of Lisbon was first created over a century ago quite by accident.

One man's remarkable private collection of art from around the world.

The best place in the world to buy tinned fish.

One of the smallest bookstores on the planet.

A garden in Lisbon filled with giant porcelain creatures.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

The world's oldest bookshop still in operation.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

Along the most northwestern point in Africa is an ancient cave surrounded by legends.

A five-square-mile slice of Spain on the Mediterranean coast of North Africa.

A beautiful but toxic fountain of mercury.

This cemetery features modernist statues as strange as its name.

Giant topiary dog once played a role in a terrorist bomb plot.

This 19th-century fountain's namesake animal isn't what you think it is.

Bold black and white motifs of life and death add a dramatic flair to this 17th-century crypt.

This abandoned mansion has a window for every day of the year, and is a temple for ghost hunters.

The mysterious large white cross visible from the runway is a memorial to a massacre during Spanish Civil War.

Shrapnel, dynamite, bullets and Franco couldn't destroy this bust, rescued and kept hidden as a family secret for over 40 years.