Elevated freight railway turned wildly successful urban park.

A drawbridge named for a potentially intersex Polish national who fought alongside George Washington during the American Revolution, and an example of "Pulaski Red".

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.

The longest continuous underwater road in North America was built at the insistence of Franklin Roosevelt.

Once a dumping spot, now a park with a kayak launch.

A decommissioned military complex that's now a modern industrial park.

Walk into the 19th century without leaving Brooklyn.

One of the most enjoyable bits of history at Coney Island and “the most romantic ride in the world.”

Since 1973, this block has been home to the most concentrated collection of murals in San Francisco.

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

A winding path built in secret on the edge of the continent.

A former utopian healing center created by a huckster and built by derelicts.

California's oldest wind harp represents a historic piece of America's Danish history.

Windswept and remote, this island was once the home of a rare mammoth and today is home to a rare tree.

Hundreds of trees made from glass bottles make up this forest on Route 66.

Carved by a waterfall in a hard-to-reach rock formation, this heart-shaped rock has inspired romantics for decades.

Oldest building in California still in use.

Named after a bandit and the star of several Hollywood prehistoric landscapes, these sandstone formations are a historical part of the Los Angeles natural landscape.

From Japan to Italy, this California park explores the world's cultures through their gardens.

The show's fictional Korean medical camp was created in the Santa Monica hills.

A "haunted" landmark on the coast of Southern California.

A Swedenborgian glass church surrounded by redwoods sits perched atop a massive landslide area.