An abandoned NSA listening post on Berlin's "Devil's Mountain."

Thousands of coffin-like pillars make up this controversial Holocaust memorial.

Christ's blood preserved in a Belgian town.

Something's watching you.

This communist behemoth is the heaviest building in the world and a legacy of a brutal regime.

A small monument in Lithuania marks the geographic center of Europe—or at least one of the claimants.

The deepest sinkhole in Central Europe comes with a grisly tale and an unusual nickname: “The Stepmother Abyss.”

This massive collection of taxidermy is full of specimens collected by missionaries during their international travels.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

Remnants of an exploded schooner and wrecked submarines form a breakwater.

One of downtown Berlin's last reminders of its Communist past.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

A hidden church in a hidden courtyard tells the story of the Miracle of Amsterdam.

Amsterdam's former hotspot for public executions and dissections.

The 20-mile causeway that separates the Netherlands from the sea.

The largest flower auction house in the world.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

A public urinal so pretty, it was declared a national monument.

Go inside a revolutionary, cage-less zoo where 70 species of monkeys roam free alongside their human visitors.

This fairy tale forest hides scenes from some of the more obscure and bizarre Western nursery stories.

This small town in the Netherlands has no roads but instead, miles of canals and over 100 bridges.

A collection of items from a way of life that no longer exists.

A giant portrait of an ancient king looms over the river.

A church of bones, decorated with 40,000 human skeletons.