The birthplace of Karl Marx is now a museum dedicated to the communist revolutionary's life and work.

The original home of the Lego has a huge amusement park dedicated to the iconic plastic toy.

The old observatory in Copenhagen has a spiral corridor used as a racetrack.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Vast stretch of tide-pools with a unique Moroccan charm.

An awe-inspiring mosque in Morocco with one of the tallest minarets in the world.

France's highest manned weather station is the only one still inhabited by meteorologists.

Even France's favorite aquatic son Jacques Cousteau, couldn't get to the bottom of it.

These crumbling Nazi artillery bunkers are now fair game for massive graffiti projects.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

A natural arch carved by a river gave its name to the so-called "Cave of Forgotten Dreams."

These azure waters were thought to lead to the Mayan Underworld.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Every equinox this Maya pyramid puts on a spooky ancient light show.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

Housing the famous Norwegian ice-defying 19th century polar exploration ship.

Home to three historic ships from the age of Vikings.

It houses the remains of a 17th-century version of the Titanic.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

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

The site where one of the most famous poems of World War I was composed is preserved to honor the legacy of the work.

The highest point in Belgium is a staircase to nowhere.