Birthplace of the "Cat in the Cradle" and a cluster of iconic, original windmills that let the Dutch tame the seas.

This colorfully-painted tunnel links two distinct parts of a historic neighborhood.

The oldest skyscraper of Europe now stands dwarfed by the surrounding structures.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

A set of 27 bamboo tubes creates an eerie soundscape that changes with the wind.

A 1:20 scale piece of the Netherlands commissioned by a queen lets visitors take a stroll as giants.

A true Valhalla for cactus and succulent lovers.

These slanted cubic abodes are a creative if odd solution to a zoning pickle.

This unusual elevator doesn’t stop or slow down.

A floating cat sanctuary on an Amsterdam canal.

Cat art as far as the eye can see.

Established in 1638 to battle the Black Death, Hortus Botanicus Amsterdam is a treasure trove of rare flora.

Seven mini rowhouses fill the gap between 54 and 70 Westerstraat.

The world's only museum devoted to the wonders of fluorescence.

The only gallery in New York dedicated to olfactory art and the exploration of scent in art.

Peek through the gates at this oasis from the city, full of Old English charm.

The walls are decorated with whimsical murals painted by the creator of the Madeline franchise.

Hidden in Central Park's Ramble is a troublesome cave buried just beneath the surface.

An extensive collection of fine art devoted to man's best friend.

Hidden in plain sight on a pair of Manhattan subway tunnels are a pair of public instruments that sing to each other.

The world's oldest hologram gallery and the labyrinthine laser laboratory of a holography pioneer.

This outdoor gallery of sculptures along the East River was once a landfill.

A self-made museum in Queens, New York continues to display the work of a sculptor known for paving his own way.

A little lighthouse in New York City, surrounded by mysterious stories of insanity-driven construction.