Mark Twain once stopped at this rest station during his journey to Nevada.

A popular rock that acted as a waymarker for American pioneers.

Native Americans built this circle of stones, which was used to predict astronomical events.

This shrine is an ode to the region's rich Hispanic heritage.

A long and winding trail through history led to the current iteration of this mountaintop tower.

The first railway tunnel to cross the Continental Divide and, at 11,523 feet, was once the highest railroad tunnel in the world.

A short but powerful waterfall resides amid Colorado’s Great Sand Dunes.

This Colorado fire station has been in continuous operation for more than a century.

Ute tour guides have been sharing the ancient dwellings and rock art inside this large park with visitors for more than 40 years.

Two tall rocks sit at the center of this site, once the home of a large Ancestral Puebloan community.

All that remains of this once-booming mining town are the ruins of a saloon.

This remote Colorado canyon is home to the second-largest collection of natural arches in the world.

A small store filled with animal skulls and other curiosities.

This nearly abandoned town was once a thriving mining community until a series of fires.

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

The only thing sweeter than the potatoes is the canine proprietor of this roadside stall.

Happen to come across a dead eagle? Send it to America's official dead eagle warehouse.

A short hike into the mountainside forest reveals a decaying 1890s town.

The remains of a failed attempt at medieval nerdery are hidden deep in the woods of Virginia.

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

A crumbling hospital from the 1850s on Roosevelt Island.

A Beaux-Arts triumph rises from decades of decay to become the heart of a new innovation district

See just what life was like in a 19th-century prospecting town.

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.