Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

An outdoor sculpture park of giant pink robots and post-apocalyptic Christmas scenes.

An inconspicuous footbridge beloved by San Diego locals.

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

Canyon walls shrouded in ferns.

Quite simply the largest tree in the world (by volume).

This strange seaside tower got its name from a wealthy eccentric who would hide coins among its stones.

A "gravitational anomaly" located in the redwood forests just outside of Santa Cruz, California.

The ghostly remains of an accidental sea.

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

A hand-built folk art installation covered with messages of God's love.

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

A modern day curiosity cabinet.

Home to items never before seen by the public.

The hike through a narrow river flanked by the 2,000-foot-tall walls of Zion Canyon is one of the best in the world.

The deepest lake in the United States, and once the site of epic destruction that lives on in legends.

Where America's first doomsday cult awaited the end of the world.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

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

Explore the largest pure gypsum deposit in the world, and go dune sledding while you're at it.

A roaring, awe-inspiring double cascade of icy water flows through woodland Oregon like something out of a Tolkien novel.

Elevated freight railway turned wildly successful urban park.

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

America's most famous museum of medical oddities is home to the remains of Albert Einstein's brain.