In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

A winding path built in secret on the edge of the continent.

Bring your own cardboard to the slippery slopes of concrete hidden in a neighborhood park.

An artsy hidden staircase leads to breathtaking views of San Francisco.

A huge musical instrument played by the ocean.

This lab's maddening silence is good for business but bad for sanity.

This Wall Street bar was once a hub of revolutionary activity where Washington famously bid farewell to his troops.

A treasure hunter's tiny bar, harboring celebrities since 1959.

A sign at the end of the Santa Monica Pier marks the traditional end of the legendary American highway.

These banned cigarette vending machines now sell little pieces of pocket-sized art.

A micronation on an islet along the coast of a Portuguese island.

Men in rubber-soled boots serve as your "brakes" on this toboggan ride Hemingway described as "exhilarating."

Portugal’s highest lighthouse has one of the most impressive focal planes in the world.

Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

This amazing abuela became a diehard metal fan late in life and an icon of Madrid's '80s rock scene.

In the fictional world of Kcymaerxthaere, celestial wonders marked a portal to a powerful route of travel at this site in Madrid, Spain.

The earliest known map to show America, discovered by accident at a Paris bookshop.

The R&B singer's modest church guarantees a religious experience, regardless of your beliefs.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

The secret city built by the Manhattan Project.

This replica of the Greek structure is in the heart of Nashville.

The titular fictional logger only inhabits this otherwise historically focussed museum via a piece of fiberglass kitsch.

A town filled with hot chocolate, dazzling lights, and lots of Christmas cheer.

A collection of 1,300 accordions of all shapes and sizes displayed in chronological order.