An optical illusion found amid a logged redwood forest.

Non-profit time travel mart sells goods you would need for a trip through the fourth dimension.

These colossal desert barcodes have been fine-tuning spy satellites for decades.

Finale of "William Tell Overture" can be heard as drivers pass over grooves in the road.

The now-abandoned tunnels were built for the transcontinental railroad on the route where the first wagon train entered California.

Eastern zen meets Western grit in these four little trees growing out of a rock on Lake Tahoe’s Nevada shore.

A breathtaking 19th-century trail overlooks Lake Tahoe.

This historic estate on the east shore of Lake Tahoe was home to an eccentric millionaire (and his pet elephant, Mingo).

A rough granite monument marks the spot where Europeans first caught sight of the San Francisco Bay.

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

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

One of only five observatories in the world built to measure the Earth's wobble.

The mysterious round rocks of Schooner Gulch.

The private clubhouse for the members of the Academy of Magical Arts.

An unfortunate geological resemblance to Satan has labeled this Pasadena gorge as a passage to the underworld.

The blinking light atop the iconic landmark has been sending secret messages for decades.

Gold Rush-era tombstones line the park's paths.

Longtime headquarters of controversial boys' club for the world's wealthiest and most powerful.

The oldest burial ground in the city, final resting place of city founders, Ohlone natives and murderers alike.

Visible below the waves are memorials to the city's Gold Rush dead.

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

A huge musical instrument played by the ocean.

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.

An abandoned Cold War missile radar site.