Explore 10 acres of environmental sculptures.

The seamy, underground secrets of Portland's criminal past.

Alleyway plaque commemorating the death of a fictional character in The Maltese Falcon, not far from the author's home.

No need to strap in for a "ride" on this walkable roller coaster.

A tiny microvalley etched into the side of Knocknarea Mountain hides another world.

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

An offbeat angle on the ocean viewed through an antiquated lens.

On a quiet suburban street stands a peculiarly decorated house covered in mosaics.

Shop selling 500 flavors of soda has something for everyone.

A hyper-luxurious, 12,000- square foot home might be buried beneath Queens, still waiting to protect you from nuclear missiles.

An entire town preserved as a historic landmark.

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

Post office plaque commemorates local resistance to a cult invasion.

The largest collection of two headed animals in the world.

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

Left untouched since a double murder-suicide in the 1960s, Los Feliz murder mansion remains a neighborhood mystery.

The one-time watch house for incoming ships at the Golden Gate now stands abandoned and hidden in trees.

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

Suburban observatory was personal lab of the father of modern astrophysics.

One of the world's largest telescopes, stares into the night sky with two huge mirrors.

A museum built around a bus-sized fossil on the side of the highway.

Odd outsider art installations surround a Gold Rush-era ghost town.

Experience a quartz crystal sound bath inside a storied, all-wood sound-chamber.

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