The key to turning shifting dunes into the green oasis of Golden Gate Park.

Once the largest windmill outside of Holland, with enormous 114 foot sails.

A walk-in working camera obscura produces 360-degree live images of the San Francisco coast.

The seawater playground of gilded-era San Francisco burned to the ground in 1966.

San Francisco's urban bison herd has persisted in the face of extinction, development, and disease.

A modern mechanical planetary system, part of a 10,000 year clock.

Decades after testing the polio vaccine on unwitting patients, this historic mental hospital sits in ruin.

Experience architect Le Corbusier's modernist design for living in the home he designed for himself.

A museum which takes visitors to the côté obscure of Paris.

Behind the Cowboy Hall of Fame is a burial ground for good horses and a famed rodeo bull.

The headquarters of the famous Yale society.

137 graves holding New England's earliest residents.

The studio of influential composer Charles Ives is perfectly reconstructed, hidden in the back of the American Academy of Arts and Letters.

Used as an example in one of the first dictionary entries for "museum" in 1706.

A simple plaque remembers an act of WWI terrorism that obliterated an island and forever scarred the Statue of Liberty.

This museum holds not just a world class collection of firefighting artifacts and gear but even the region's first fire station itself.

Sitting in the arguable birthplace of the Wild West, this museum holds the largest collection of bronco busting bric-a-brac in the world.

Home of Philip Johnson, one of the 20th century's most influential architects.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

A curious fountain that has no water and includes Satan, a crab, and 9 giraffes.

The curious underground history of keeping Paris clean.

The ancient dwellings of the Puebloans, located in the cliffs of majestic mesas.

London's creepiest cemetery was once the site of dueling magicians and mobs of stake-carrying vampire hunters.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.