An inconspicuous footbridge beloved by San Diego locals.

Four miles of pipelines form the model of still-functioning retro-tech efficiency.

The beauty and the beast of hydraulic mining is on full display at this California Historic State Park.

The Mighty Wurlitzer organ continues to belt out the tunes at downtown El Segundo's historic home for silent and classic movies.

One time home to turn of the century explosives, now hidden under the Bay Bridge.

A lovely summer day by the sea becomes a nightmare.

Large but largely ignored, these 42 life-size Liberty Bell replicas were a peculiar, unexplained feature on the facade of a Macy's department store.

An enormous artwork that colorfully celebrates over 150 years of US military achievements.

An ominous concrete cube cuts a dystopian silhouette atop this California mountain.

This concrete ship has had four careers - World War I tanker, floating amusement park, fishing pier, and artificial reef.

This odd little museum holds exhibits on everything from blacksmith equipment to hair jewelry.

Where the alchemists dream of transmuting base metal into gold was actually achieved.

Once the fastest ship from San Francisco to Tahiti, the Galilee now lays in pieces in three different cities.

A miniature view of the park, caught in time.

This California tree is the single source of the state's entire orange industry.

This ultra-modern California span is actually a titanic solar clock in disguise built by famed architect Santiago Calatrava.

This crumbling Death Valley mining complex was known for its use of giant, 20-mule team wagons.

Not truly a ship nor a building, the Navy's first and last "landship" is now abandoned due to clerical issues.

A repository of Pasadena history.

Working mining and drilling equipment demonstrate 150 years of energy history.

Prone to disastrous fires, the city of San Francisco has the Guardian, a fireboat gifted by residents, to watch over them from the bay.

A lighthouse built to save lives that took quite a few with its treacherous location.

Hidden beneath a lake for decades, this brutalist mine has now emerged from beneath the receding waters.

Built by one man in the '20s, this site is now a museum representing the Great Basin cultures.