A sealed test tube said to hold Thomas Edison's dying breath was given to the inventor's friend and mentee, Henry Ford.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

The only surviving prototype for Buckminster Fuller's house of the future.

When you visit his grave, be sure to rub the Great Emancipator's nose for good luck.

A tribute to Ponce de Leon's supposed quest for eternal youth.

Strange physical sensations and optical contradictions keep visitors coming back for more.

A series of waterfalls so massive they straddle the border of Argentina and Brazil.

This red-eyed chrome beast pays homage to the popular modern myth of West Virginia's insectoid monster.

A small storefront museum explores the history and myth of West Virginia's famous urban legend.

A historic house in St. Louis was plagued by a series of suicides committed by family members involved in a successful brewery.

These sub-farmland caves are home to a majestic stalactite known as the "Crystal King."

400 million-year old limestone caverns nestled in the Ozarks served as shelter and a hideout for cultures throughout North American history.

The longest navigable underground river in the United States is home to countless blind and albino animals.

One of nature's most well-scheduled phenomenons resides in Wyoming's Yellowstone National Park.

A house carved into a rock in the 1940s.

This one-time health resort was used by aristocrats around the world.

The granddaddy of all tourist traps, built on ice water, jackalopes, and a giant dinosaur.

Sparkling, calcite-covered skeletons of children who may have been sacrificed to appease an angry god.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

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

Less a museum than a bizarre fantasy world created by artists and engineers.

The world's longest known cave system.

The first declared National Monument in the United States.

Enormous lake at the bottom of a unique cave system.