This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

A wonderful display of arts and crafts handmade by local artisans in the Southern Appalachians.

A six-foot pair of socks hangs from a drawer of the world's largest bureau.

This research center for rare prosimians is studying how they sleep to help prolong human life.

The highest point in North Carolina and the United States east of the Mississippi River, Mount Mitchell is named after argumentative explorer Elisha Mitchell.

The highest point in Tennessee, Clingmans Dome bears witness to the ravages of one type of insect.

The romance of early commercial flight still fills this Art Deco destination.

The Kirkland Monument remembers a selfless Civil War hero who braved the battlefield to give water to his dying enemies.

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

This isn't your average roadway—it's actually a National Park and a transportation pioneer.

This beautiful vintage movie palace has seen little change in form or function since the 1920s.

The graveyard holding the remains of George Washington's slaves was forgotten for nearly 200 years.

This lovely picnic spot featuring thunderous jet landings is an aircraft spotter’s dream.

Collecting 700 years of mechanical death-dealing, the NRA's sprawling gun museum is a revealing testament to the American obsession with armament.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

A dramatic, 360-degree recreation of Pickett's Charge in the Civil War.

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

Yo, Adrian!

This charming colonial alleyway is one of the oldest continuously used residential streets in the U.S.

Found art has transformed this Pittsburgh neighborhood into a psychedelic dream.

Tour the dark and beloved poet's former cobwebbed basement, which may have inspired "The Black Cat."

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

The ruins of this long-abandoned unsuccessful gold mine can still be found.