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

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

During an annual Catholic feast in this tiny Spanish village, men dressed as devils leap over rows of babies to cleanse them of sin.

This small chapel is built of human bones and decorated with a golden skeleton.

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

Houses are tucked between, on, and underneath giant boulders.

One of the most breathtaking railways in Europe also takes one of the steepest climbs, from fjord to mountain plateau.

This gaping hole in the middle of a remote mountain lake looks like a portal to another dimension.

This tower once served as a radar station during the Cold War.

"Portugal's Stonehenge" is made up of nut-like stones aligned with the heavens.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

When this former hospital pharmacy closed in 2013 it already looked like a museum, so they turned it into one.

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

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

The most elaborate of 12 medieval arched doorways to the old city of Burgos.

Nature is slowly overtaking this disused cemetery on the outskirts of Brussels.

This legendary giant, born from vegetables, terrorized townspeople and cheated local children in games.

Hidden along this old street in Antwerp is a surreal monument of a bronze arm sprouting four hands.

According to this bar, God gave an “11th commandment” to Antwerp: Thou shalt drink beer.

A man throwing a giant severed hand towers over Antwerp’s main square.

To enter this cluttered-yet-cozy sanctum of Belgian brews, ring the bell and tell the gatekeepers you've come “to taste beer.”

This statue dedicated to the story of a Flemish boy and his dog was relatively obscure in Belgium, but a cult sensation in Japan.

This small corner bar is home to a rare 1930s dance organ that still plays tunes for one Euro.

The patron of this extravagant Art Nouveau confection insisted that nothing less than a boat should project from its facade.