A tiny museum housed in a New York freight elevator specializes in the "overlooked, dismissed, or ignored."

A crumbling hospital from the 1850s on Roosevelt Island.

La Monte Young and Marian Zazeela's "Dream House" will immerse you in an ever changing world of sound and light.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

A rescue facility that caters specifically to wolf-dog hybrids, and educates about these unique animals.

This ghost-town bar has bullet holes and plenty of stories lurking within its walls.

This whimsical fountain pays tribute to Toronto's four-legged friends.

Lost subway station nestled beneath Toronto's busy commuter line.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

A botanically themed auditorium blooms within the world’s last operating double-decker theater.

One of Canada's most incredible rare book collections holds hundreds of thousands of gorgeous tomes that the general public can touch.

A book collector's dream, this Toronto bookstore has the world's first "Biblio-Mat," a random book vending machine.

The ruins of Vancouver's abandoned heritage railway.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

Hear the quietest sound from across the dome.

Wedged between two buildings at the Great Ormond Street Hospital is this secret music installation.

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

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

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

A tongue-in-cheek arcade where the games are based on everyday life.

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

The perfectly preserved underground rooms where Churchill plotted the war against Germany.

The popularity of Sherlock Holmes led to the creation of his fictional address, turning the orderly London street numbers askew.

An easily overlooked stretch of ornate window fronts and gaslight lamps that could be right from the pages of Dickens.