A partial tunnel blasted into a steep ridge is all that remains of a failed railway across Arizona.

The eroded core of an ancient volcano is now accessible by a short hike.

Beneath a Virginia City bar is the entrance to an abandoned gold mine.

This immigrant bridge once spanned the Thames but is now a fixture of an Arizona city.

This memorial pyramid marker honors one of the United States Government's first official camel riders.

The "world's biggest dinosaur" once housed a creationist museum in its abdomen.

A dwindling menagerie of anthropomorphic oil derrick animals still dot the barren California landscape.

Where the writer penned his famous story about a jumping frog.

The world's first permanently occupied mountain-top observatory continues to report on the stars.

It should come as no surprise that the world's largest artichoke lies in the town that calls itself the "Artichoke Center of the World."

Twenty-seven massive radio antennas on the high plains of New Mexico search for life on other planets.

Twice a year, visitors can tour the desolate site that birthed the Atomic Age.

A one-of-a-kind sundial at the Very Large Array honors a radio astronomy pioneer, incorporating the original piers from his breakthrough radio telescope.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

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

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

A cabinet of curious mathematical models and old calculators.

Sleep where gangsters fell amidst smoke and flame, with nary a bullethole to show for the legendary struggle.

A natural history wunderkammer in the middle of the desert.

A reproduction of earth's many biomes.

Take a monster truck tour around an ostrich farm in the middle of the desert.

The largest natural travertine bridge in the world is nestled in a small canyon in central Arizona.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

A towering bronze statue memorializes the founding father of postwar American conservatism.