Limestone caves with spectacular showcase chambers.

Ancestral Puebloan ruins, natural arches, and box canyons abound in this seldom-visited corner of Monument Valley Navajo Tribal Park.

A stealthy Apache hideaway that became the haunting site of a mass grave.

An arsenic-filled pool in the Grand Canyon takes on the appearance of a giant, overflowing pumpkin.

This secluded aqua waterfall in the Grand Canyon is the perfect swimming hole, and the Havasupai tribe's fiercely protected natural wonder.

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

Steep canyon walls hide a forested oasis in the West Texas desert.

A 131-year-old wunderkammer of Texas history.

One of the most remote spots in America and the first protected wilderness area in Nevada, named after an old legend.

A geological oddity formed by two rivers carving out a mass of limestone on both sides.

A house turned museum is the real-life "home" of the fictional main character of The Wizard of Oz.

Twenty churches beautifully painted by 19th-century Czech and German immigrants in Texas.

This protected area in Lake Huron contains some of the world’s best-preserved shipwrecks.

This soda factory is one of the last in America to use real cane sugar despite the protestations of Dr Pepper.

It specializes in outsider art and artifacts of secret societies.

This massive store is home to an eccentric collection of vintage, retro, and peculiar goods.

A strange history museum, with items accumulated by a pair of globe trotting spies.

The former home of the hard partying literary power couple is now one of the only museums devoted to their story.

Every last book in this bookstore is signed by the author.

This picturesque cliffside beacon no longer calls to sailors but shines once a year in honor of a famous shipwreck.

The home made famous by the 1983 holiday classic is now a perfectly preserved shrine to the movie.

This cave holds a surprisingly colorful variety of geological oddities.

A bizarre house filled with an astounding array of collections.

The end of the 4 Line is also the end of the line for 300,000 souls in one of NYC's most illustrious cemeteries.