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

In Tucson a giant metal snake helps pedestrians cross a busy highway.

A reproduction of earth's many biomes.

See massive fossils that are over 200 million years old in northeastern Arizona.

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

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

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

This replica stave church looks like a piece of Norway was simply plopped down in South Dakota.

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

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

Air Force Academy Chapel made of 100 identical tetrahedrons works to inspire those of all religions.

One man’s passion for gas stations is on display along the Rio Grande in northern New Mexico.

A unique geological area spiked with wind-carved rocks that resemble teepees.

An immersive environment that is part haunted house, part choose-your-own-adventure, and part jungle gym.

A museum devoted entirely to the rattlesnakes and snake-related art.

The official atomic museum of the United States explores the explosive and productive history of a much maligned energy source.

This is one really big nut.

This fast-food outlet is the only space and UFO-themed McDonalds in the world.

A museum dedicated to the alleged Roswell Incident.

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

A world-class observatory in the California desert.

An historic and oft-filmed spot for musclebound iron pumpers on the Pacific coast.

Rainbow-hued local gem in Venice.

California's own medieval Italian castle, authentic down to the 300-year-old iron maiden in the dungeon.