A mysterious ancient cemetery with Roman sarcophagi and Lycian inscriptions.

Roman ruins top white travertine terraces formed by ancient hot springs.

A deadly ancient portal to the underworld.

This hunter-gatherer architecture is believed to be the oldest religious complex known.

A monumental cross hides in the trees in Golden Gate Park.

A Mysterious Masonic tomb in San Luis Obispo.

The only surviving prototype of Buckminster Fuller's revolutionary car.

A massive volcanic plug is now a protected area that hosts a number of bird species.

A trash dump made beautiful by nature's power.

The fossilized remains of ancient California redwoods.

Towering basalt columns, a creation of fire and ice.

Law-protected wreckage serves as a peculiar memorial for an almost forgotten World War II tragedy.

The largest drain hole in the world.

A miniature view of the park, caught in time.

A working model of the entire San Francisco Bay and much of the Sacramento River Delta, complete with regular tides that change every 14 minutes.

A hidden subterranean installation offers a view of the sky.

An artsy hidden staircase leads to breathtaking views of San Francisco.

The stones that traveled from Spain to eventually become a holy place for San Francisco's nature worshippers.

A vast city of the dead, where the deceased outnumber the living by more than a million.

The restored and active Victorian-era final resting place of San Francisco.

The final resting place of the Emperor of the United States and Protector of Mexico.

Seven ceramic sculptures are scattered around this California college campus.

A huge musical instrument played by the ocean.

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