A sculpture of a flying hawk made from colorful car doors.

The U.S. Air Force has an anti-satellite laser weapon.

The second-largest cave chamber in the world was discovered in 1898 by a 16-year-old and a friend known as "Pothead."

Wee (and not so wee) footprints that insects and reptiles of the Paleozoic Era left behind.

The outcropping is graffitied with the name of the beloved musical Muppet television series.

The world's first commercial spaceport is a disappointment of cosmic proportions.

This quirky hot springs town known to locals as "T or C" was named after a radio show.

Deadly airliner crash preserved for those willing to climb and pay respects.

After a short-lived attempt to bring America in line with the rest of the world, this road was left in metric.

Make a wish at what might be America's only Catholic shrine to a sinner.

A living snapshot of a different time in America is preserved and maintained by a community of volunteers.

Stairs often replace streets on the steep slopes of this old mining town.

Limestone caves with spectacular showcase chambers.

The second building of its name to occupy this location might be the finest flatiron building in San Francisco.

Only hotel where you can legally launder money.

Guns that have been defending San Francisco since 1904.

An elaborate gift from Claus Spreckels is now a piece of San Francisco history.

A man-made island in scenic San Francisco Bay.

The giant pair of sexy legs sticking out the window of this costume store have become its main draw.

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

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

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

A collection of 20th-century automata, penny arcade games, and musical contraptions.

San Francisco's newly reopened hands-on science museum.