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

Bootleggers ran booze beneath this building before (and after) Route 66 appeared beside it.

This oasis-like spring in the Sonoran Desert is home to unique, endangered species.

This bomb shelter-themed bar has barely changed since it opened.

Giant telescope mirrors built in a spinning furnace under a college football stadium.

The Magical World of George Phar Legler.

A strenuous, unofficial trail leads to spectacular views in one of America's most remote national monuments.

This scrap yard doubles as a naive art gallery full of found art and farm animals.

An excursion train traverses a picturesque red-rock canyon along the Verde River.

Once the product of an inexplicable gold strike, this ghost town is now home to one man and his love of classic machines.

The largest and most well-preserved petroglyph site in the Verde Valley.

Concrete crosses scattered across the Arizona scrubland which were used to align spy satellites.

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

These petroglyphs created by ancient Arizonians have withstood centuries of exposure to the elements.

A self-built castle made by a mysterious man.

A mysterious "wedding cake" castle in the middle of the urban desert.

Open since 1938, this diner has kept its fountain, malt machine, and all the gum that greasers left beneath its counter.

Some 10,000 works of ancient rock art cover these volcanic basalt outcrops near the Gila River.

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

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

A once popular resort—said to be the vacation spot of gangster Al Capone—now remains abandoned in the woods of Arizona.

An urban laboratory.

Puerto Rico's oldest rum producer started its 140-year-old business with "a little barrel."

On a small Puerto Rican island, banks of secret naval bunkers lie abandoned and filled with piles of office equipment.