A tree-like building perches on its trunk in the Steglitz neighborhood of Berlin.

The largest free-standing aquarium in the world resides in a hotel lobby in Berlin.

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

Berlin's old airport.

Berlin's natural history museum houses the world's largest mounted dinosaur and the late beloved polar bear Knut.

Art and a pun, all in one.

This water-tower-turned-high-end-apartment building was once the site of an early Nazi concentration camp.

Cold war icon and onetime "hole" in the iron curtain.

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

Beneath Denmark's Højbro bridge, a bronze merman and his seven sons forever mourn for the mother and wife who left them for land.

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

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

Old Danish castle immortalized in Shakespeare's Hamlet.

An ultra-modern diversity park in Denmark has turned an entire city block electric pink.

Iceland's "Smoky Valley" is a beautiful river that is shrouded in a constant cover of steam clouds.

Walk in the footsteps of the gods and straddle two tectonic plates.

A collection of noses tucked inside an art museum reveals how times have changed.

Three columns of volcanic rock shoot out of the ocean.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

An encyclopedic collection of mammal penises.

This fantastical waterfall is hidden in a cave located in a cracked cliff.

The picturesque birthplace of Icelandic democracy is drenched in the blood of its brutal past.

This bridge was the birthplace of a unit of measurement based on a fraternity joke.

This cemetery served as the only official burial grounds in Cambridge for nearly 200 years.