The best place in the park to test out your throwing arm.

One of few lasting examples of the brief octagon craze that developed into folly.

Spiral labyrinth hidden in the hills above Oakland, CA.

An abandoned car and strange wooden debris are among the scattered remains of the old sand and gravel quarry.

At night, a grove of towering redwood trees growing through the pavement block out all light from the so-called “Dark Park” of Madrone Avenue.

Internationally-recognized arts center housed in a century-old former military barracks.

This small monument to the great inventor contains a time capsule and a Wi-Fi hotspot.

The world's most famous donkey lives in this pen.

San Francisco’s condensed garden of incredible plant growth.

A second generation sun-powered marvel lights up the night.

Thousands of migrating monarchs overwinter clustered amongst the eucalyptus trees.

This unconventional used book store was once in the news for the surprising act of burning books.

A 250 million-year-old rock formation has earned a rather unique nickname.

Explore the wide world of desert plants at this unique Palm Springs botanical garden.

An imperial church bombed to ruins during WWII now stands as a jagged memorial.

This bridge was the birthplace of a unit of measurement based on a fraternity joke.

A favorite haunt of dinosaur loving children and hallucinogen loving hippies alike.

This remote island, home to the easternmost point in Denmark, once hosted pirates and a military fortress.

Built from one couple’s vast personal collection, this free museum showcases a century’s worth of state-sponsored agitprop.

Barely visible foundations remain where Stow Lake’s “observatory” once welcomed visitors.

Adolph Sutro's little-known, geographically inaccurate, deprecated monument.

This eatery transports diners to a place that no longer exists: East Germany.

San Francisco’s century-old Christmas Tree.

Instead of faces, these sculptures have barcodes—statements on societal dehumanization.