Ten 25-foot-tall, beehive-shaped kilns, abandoned in Death Valley.

A popular tourist cave with a dark past.

A blank headstone topped with a pile of pennies marks the final resting place of the infamous assassin.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

The highest point in Maine is a grand gift to the state citizens that also happens to be one end of the Appalachian Trail.

Massive crater in central Oregon.

When the Austin Dam failed it destroyed much of Austin...and then it failed again.

Erosion and time have created a naturally-formed water park.

The only Florida state park with publicly accessible caves.

Where scientists keep miles of very valuable ice from Antarctica and Greenland from melting.

At Chicago's revered Field Museum, visitors are invited to learn about and literally explore DNA.

Faces carved into the cliffs create an otherworldly walking trail.

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

Home to the deepest rift anywhere on Earth.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

“Invented in Key West, Perfected in Brooklyn."

A large instrument played by the wind.

New fungal and bacterial species call this deadly lake home.

The former home of Samuel Clemens and family remembers the happiest period of the author's life.

This amazingly preserved Gold Rush town is a historian's dream.

The largest natural travertine bridge in the world is nestled in a small canyon in central Arizona.

Once America's longest-manned military fort, now an abandoned hulk.

Hundreds of hopeful gold miners came here to get rich, but only two years later the small town was deserted.

A small metropolis of Pueblo cave dwellings have been carved right into the hillside of this national monument.