A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

Relics from as far back as the 16th century are on display in a city known for its playing card industry.

Descend into the tunnels to experience the life of a coal miner.

This bike path traverses the treetops.

This giant urban staircase was built to keep the city's brave fighting men from getting waylaid in the red light district.

This sprawling Belgian fort was once thought of as impenetrable but now it is simply an abandoned relic.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

Incredible labyrinth of man made caves.

This historical Netherlands fortress still bears the marks of its single siege.

A Belgian self-built tower inspired by the Bible and ancient civilizations.

A pilgrimage site where people ask Saint Dymphna to watch over those who are not of sound mind.

Petting this mysterious iron monkey supposedly brings good luck.

The "Prussian Versailles" that is as glorious today as when it was built.

This monumental work of art symbolizes the coming together of a previously divided city.

A monument to the three wars that led to German unification towers within a Berlin traffic circle.

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

The curious underground history of keeping Paris clean.

Paris' fabled purveyor of exotic taxidermy and natural history curios.

This museum houses an imposing skeleton army comprised of creatures great and small.

Natural history museum celebrating biodiversity with a parade of taxidermy animals.

A haunting collection of the vanished and disappearing natural world.

France's national museum of scientific and industrial instruments.

The celebrated eyesore created by starry-eyed sweethearts.