Huge concrete structures designed as an early warning system for Britain to detect enemy aircraft.

A military vehicle collection, showcasing how war transportation advanced from horse drawn artillery to self propelled cannons.

Another of California's unused Cold War missile defense complexes has become a graffiti gallery.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

Built in just a little over a week this preserved bunker was created to protect our most attractive POTUS while he was on vacation.

America's post-nuclear-attack chambers of Congress.

Seller of surplus nuclear research materials.

Last remaining nuclear missile base in Ukraine.

This beautiful natural train tunnel is said to grant the wishes of visiting lovebirds.

A fitting attraction for the corn capital of the world.

The Giant Lemon of Lemon Grove.

Guns that have been defending San Francisco since 1904.

America's most famous piece of self-built architecture.

In a city filled with Frank Gehry buildings, one stands out as one of the architect's weirder works.

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

Russian history in San Francisco.

Not merely a museum – but a whirring powerhouse that offers a subterranean peek into the heart and soul of cable car operations.

Commonly referred to as the most photographed Victorian home in the United States.

An offbeat angle on the ocean viewed through an antiquated lens.

Most famous work of one of Frank Lloyd Wright's sons.

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

The only museum of sake in the United States is nestled in an unlikely California college town.

A giant donut stands as a popular symbol of Los Angeles iconography.

Former 1954 Del Mar Train Station now serves signature cocktails and delightful culinary treats, and still operates as a Metro stop.