Alleyway plaque commemorating the death of a fictional character in The Maltese Falcon, not far from the author's home.

Created in 1972, the famous sculptor's intricately detailed monument to San Francisco is overflowing with city landmarks.

Only hotel where you can legally launder money.

America's oldest Italian restaurant is a San Francisco institution.

The largest drain hole in the world.

The only parking meter in the entire town, it is surrounded by 100 free spaces.

If you dial the number in this abandoned office window "Sam Spade’s" secretary will ask you to leave a message.

Special tunnels built so that frogs won't be killed when crossing the highway.

Wool processing mill in an unlikely location.

Once the largest town in eastern Yuba County now sits abandoned.

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

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.

One woman's Viking Castle on Lake Tahoe.

The only road through the heart of Glacier National Park.

This off-the-beaten-path abandoned town is a relic of Montana's silver mining boom.

This prehistoric sinkhole lured exclusively male mammoths to their death, much to the delight of science.

The first declared National Monument in the United States.

The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

The highest point in South Dakota contains the ashes of Valentine McGillycuudy, the "Holy White Man."

Every president in history is immortalized in bronze in downtown Rapid City.

One of America's first dinosaur parks gives a window into Depression-era paleontology.

Thanks to a loophole in property ownership, this alleyway has become a cacophonous street gallery.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.