The second-largest gold nugget in existence, displayed in a Las Vegas casino conveniently named the Golden Nugget.

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

An architect's childhood fantasy treehouse made real.

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

The largest hot spring in the United States is, as the name suggests, a stunning show of natural color.

A beautiful geyser under environmental threat.

The only road through the heart of Glacier National Park.

Frank Lloyd Wright’s most iconic home dangles over a Pennsylvania waterfall.

A model of a dinosaur that was named for Andrew Carnegie stands outside the museum that also bears his name.

This Delaware River bridge is emblazoned with a catty slogan from a more prosperous time.

Once the "Eighth Wonder of the World," this iron railroad bridge was decimated by a tornado.

The United States’s oldest funicular railway glides up and down a steep Pittsburgh street.

A small granite block at this monument's base is the only part of Lincoln's Tomb outside of Illinois.

Where the oil industry began.

Could it have picked a better place to land?

This opera house along the banks of the Connecticut River has two Tony Awards to its credit but it’s never staged a single opera.

Holding multiple historical boats and an entire 19th century village, this New England attraction is the largest maritime museum in the world.

Quirky castle designed by the American actor best known for portraying Sherlock Holmes on stage.

A mysterious echo seems to defy the laws of acoustics.

This 19th century mansion façade adorned with immigrant patriotism is a symbol of Louisville’s history.

The highest paved road in North America winds its way up Mount Blue Sky in Colorado to an altitude of 14,130 feet above sea level.

The moving metal works of one troubled artist can still be viewed on his front lawn... for now.

Strange red rock formations that have been attributed to a higher power for hundreds of years.

One of the greatest heroes of the Titanic tragedy came from humble beginnings to this beautiful home.