A massive volcanic plug is now a protected area that hosts a number of bird species.

Towering basalt columns, a creation of fire and ice.

Aqueducts have dramatically changed this old lake, now home to tufa towers and its very own species of tiny brine shrimp.

Standing in a state of "arrested decay," this ghost town allows for a detailed peek into Gold Rush life in an unusually harsh climate.

This ultra-modern California span is actually a titanic solar clock in disguise built by famed architect Santiago Calatrava.

One of the most scenic stretches of road in America winds between some of the country's oldest trees.

Two mammoth statues inspired by equally tall tales lure tourists to this roadside attraction.

Allowing humans and fish alike to migrate from freshwater to saltwater and back again.

At Washington's Dulles Airport is a satellite museum (no pun intended) with three quarters of a million square feet of aircraft history.

The national park was once a plantation estate.

On the Fourth of July this area will transform into a Pompeii-like storm of falling embers and ash.

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.

The walls of the iconic dome are hollow and have a secret stairway.

This statue of the "father of television" stands prominently in the United States Capitol.

A line of blue paint marks the route of the inaugural parade.

A street in front of NASA's D.C. headquarters has been named in honor of the Black women who were essential to early spaceflight.

A museum cafe showcases Native American dishes and indigenous ingredients from across the Western Hemisphere.

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

It was once the base for a series of domestic terror attacks.

Home to items never before seen by the public.

This unique museum cafeteria showcases the history and regional diversity of African American cuisine.

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

Thousands of tourists and residents in Cologne affix "love padlocks" on the Hohenzollernbrücke Bridge to symbolize their affections.

It appears as if a man is standing behind this giant airport clock, painting the hands in real time.