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

Guns that have been defending San Francisco since 1904.

Forgotten and then destroyed by fire, this was once one of the largest saltwater swimming pools in the world.

A man-made island in scenic San Francisco Bay.

This turn of the century masterpiece has a mysterious goaty interloper.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

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

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.

A moss-covered statue of a Japanese Buddhist deity stands at a quiet temple in downtown Osaka.

This tea house was a hand-built gift from Boulder's sister city in Tajikstan.

A horse-drawn 1858 steam pumper fire engine encased in glass on the front lawn of a Michigan insurance company.

A pair of giant roadside arrows are all that remains of a former Route 66 trading post.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

A wall of chewing gum moonlights as collective art.

Historic Hull Street was actually the first street with a proper name in the Boston area.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

Mrs. Mallard and her brood are a beloved fixture in Boston Public Garden.

This experiment in the lifespan of seeds will take a century before it is complete.

Scores of vintage street lamps shine along L.A.’s Miracle Mile.

These delicate buggers are some of the rarest fossils that have bubbled up from the Tar Pits.

A storybook European village in Berkeley.

The century-old bell and clock tower at UC Berkeley is the third-tallest in the world, and has fossils.

The haunting ruins of Jack London's dream house.