An unassuming secret door once led to a legendary watering hole.

The name of this famed hospital was once a byword for the horrors of medical and psychiatric care.

The original toys that inspired the beloved children's stories are on display at the New York Public Library.

New York City's smallest piece of private property.

Ride the subways of yesteryear.

Order scoops of pandan, lychee, and black sesame at this family-run institution.

A semi-scholarly approach to sex.

Elevated freight railway turned wildly successful urban park.

A miniature rainforest is growing inside of a Midtown Manhattan office building.

Try not to get slimed in Tribeca.

The world’s oldest and biggest bookstore stocking only mystery, crime fiction, espionage, and thrillers.

The oldest family-run luncheonette in New York, last renovated in 1948, still serves food and drinks the old-fashioned way.

Dodge prohibitionists and slide through the telephone booth in Crif Dogs.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

A terrific purveyor of natural history objects and curios.

This 1920s Dutch barge is now a floating bookstore.

The world's first underground farm is in a World War II bomb shelter beneath the streets of London.

The quaint little store that is said to have inspired a famous Dickens novel was only given its name after the book was released.

One part local history, 99 parts gruesome haunted house.

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

Banksy gives themself artistic license with this piece of London street art.

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

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

A kaleidoscopic warehouse-maze of handmade neon signs.