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 site of an ancient Mississippian settlement that appears to have flourished during the 10th to 13th centuries.

A remnant of the last Ice Age, this lake is surrounded by fascinating rock formations.

This supper-club-turned-concert-venue still serves drinks at its original rotating bar.

Statue dedicated to the star of an old television show.

This steep-walled ravine contains animal-shaped formations made from sandstone.

Over thousands of years, this slot canyon was carved out of the bed of an ancient lake.

A renowned Civil War veteran, this Bald eagle now presides over the Wisconsin State Assembly.

Prayers and messages of hope decorate the ceramic tiles of this pavilion.

Three playfully immersive mini golf courses let you travel alongside your ball to the cup at this facility, which has been around since the 1950s.

A spectacular tribute to statesman and philanthropist Andrew Mellon.

An echo chamber with a waterfall wrapped around its base at the Embassy of Canada in Washington, D.C.

The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

Mysterious installations bring levity and light to a sometimes stodgy city.

D.C. once had its own tiny rival to the New York Stock Exchange.

This mysterious structure by the Washington Monument is a flood barrier designed to protect the White House against rising waters.

Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

Look closely and you’ll notice that the color changes a third of the way up the tower.

This stunning blue and gold room changed cities twice before becoming part of the Smithsonian.

This magnificent natural sandstone bridge is one of the largest in the world and is an iconic symbol for Lake Powell.

The fifth-longest natural arch in the world, and the longest outside China.

The marker offers a rare chance to be in four U.S. states at once, though there's some controversy over its geographic accuracy.