This limestone cave offers an incredible view of the Río Grande de Arecibo valley.

This charming, medieval walled village is Spain's first "book town."

The world's oldest bookshop still in operation.

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

This 1920s Dutch barge is now a floating bookstore.

Once one of the largest rooms full of books in the world, this bookstore basement is still a treat for bibliophiles.

A cozy bookstore is tucked within an old gold mine shaft beneath the cafe and ice cream shop.

This might just be the TARDIS of bookstores.

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

This iconic L.A. bookshop is housed in an abandoned bank—both symbolic and chic.

Western New York's largest independent bookstore doubles as a historical repository of all things Niagara Falls.

This enormous secondhand bookstore inside a Victorian train station sparked the "Keep Calm and Carry On" craze.

This small Catskills village has six independent bookstores and more bookshops than restaurants.

Shop for books in the New Orleans house where William Faulkner once lived.

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

Crooked windswept pines give this old forest an enchanted and magical look.

These ancient sunken lanes were naturally tunneled into the soft ground by countless footsteps.

Veryovkina Cave is more than 1.3 miles deep—the deepest known in the world.

Through the colossal entrance to this cave you'll find limestone tubs and an underground waterfall.

This massive subterranean fissure is known as the "underground Grand Canyon."

One of the largest caves in the world open to the public.

Site of the largest impact event to occur over land in Earth's recorded history.

The "Gateway to the Arctic" connects Barrow's indigenous population with the sea and its traditional industry: whaling.

The waters of these secluded falls are said to have healing powers.