Phil Mortillaro uses keys to bring art back to the Village.

A WWI fighter plane and turn-of-the-century penny candy shop are among the unexpected features of this Financial District building.

Unique antiquarian shop specializing in globes, maps, and prints.

A terrific purveyor of natural history objects and curios.

Hidden in the hills is a mysterious stone structure, known only to a few.

This life-size monument honors the legacy of a famous literary feline.

This giant sculpture made of trash is a critique of society's wastefulness.

18m long sarcophagus of a constantly growing dead prophet.

A uniquely lettered street sign marks the corner where the iconic word game was invented.

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

A touching tribute to the "Wonkey Donkey."

One of the few places where you can visit a cenote and Maya ruins at the same time.

There's a mini version of Iguazu Falls hidden in the Balkans, and it's got a rope swing.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

A meow-velous tribute to a beloved street cat, made famous on the internet.

A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

Peruse rare tomes like poetry bound in pearls or books with branches and berries growing out of their spines.

This stunning Brazilian library contains the largest collection of Portuguese texts outside of Portugal itself.

A wondrous old library overlooking the nation's capital.

A hoard of sky catalogs, astrophysical journals, even the works of Galileo and Copernicus.

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

The library of every book lover's dreams.

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