This strange hill on Old Fort Road where gravity works in reverse has been fascinating locals for years.

Trails through lava-carved tube-caves display sparkling bacteria and a rich history.

This ultra-modern California span is actually a titanic solar clock in disguise built by famed architect Santiago Calatrava.

Where a railroad loops under or over itself to rise or drop more than 70 feet in a short distance.

Thousands of turbines whir at the origin of North American wind power.

Where decommissioned airplanes and helicopters go to become part of Hollywood.

This once-booming Gold Rush town is now home to a herd of feral donkeys.

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

More than 25 fully functional scale replicas of famous lighthouses dot the shores of Lake Havasu.

This huge dam across the Colorado River caused an armed standoff between two U.S. states.

A scrap-metal sculpture recalls an infamous 19th-century camel.

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

A lingering bit of Space Race nostalgia lies in the middle of the desert.