A pair of slides and a tree-lined stair corridor have been an urban oasis for nearly 40 years.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

A Jenga-style cylindrical tower of books that appears to go on forever.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

Where beautiful signs live on forever.

This 1920s Dutch barge is now a floating bookstore.

With over 100 jam-packed rooms to explore plus elaborate tea services and events, the Mansion on O Street is a hidden treasure.

This South London cemetery holds the remains of more than 15,000 people.

The most iconic structure in Scotland has been home to bishops, colonels, and Sean Connery characters.

The intricate stonework of Machu Picchu serves as a testament to Incan engineers.

The fountain marks the area where hundreds of accused witches were burned at the stake.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

Large but largely ignored, these 42 life-size Liberty Bell replicas were a peculiar, unexplained feature on the facade of a Macy's department store.

A grove of "candelabra redwoods" deep in California's Lost Coast.

A trash dump made beautiful by nature's power.

A dilapidated dock tells the story of Titanic's missed arrival.

A one-of-a-kind collection of a unique medium.

Just your average Marie Antoinette–themed speakeasy in an abandoned 19th-century subway tunnel.

This abandoned amusement park was built on a site with a dark history.

Its buzzing collection honors vibrator history.

A museum befitting the city responsible for supplying the majority of the world's LSD.

Where manatees are the snowbird vacationers in these balmy Florida springs.

Two thousand artifacts from around the world collected by one woman who loved to travel.

A beautiful 62-acre Catholic shrine and botanical garden.