Outside the Department of Transportation, a collection of artifacts honors the history of how we get around.

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

D.C.'s first central library was born out of a chance encounter with the philanthropist whose name it bears.

This rowhouse doubles as one of the most photographed spots in the nation's capital.

The controversial urban planner who designed Washington, D.C., was buried in Maryland, and can presently be found in Virginia.

The Lincoln Memorial has inspired many, even though a word on the inscription appears to be spelled incorrectly.

The grand marble structure next to the White House is Andrew Carnegie's temple to Pan-American diplomacy.

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

The actual model from the original "Star Trek" series is now on display at the National Air and Space Museum.

The "lovely red Vega" of the legendary record-settling pilot.

While most wind tunnels test scale models, the "Cave of Winds" was large enough for actual airplanes.

This groundbreaking 16th-century map is known as "America's birth certificate."

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.

A hidden gem on the lawn of the U.S. Capitol Building designed by landscape architect Frederick Law Olmsted.

"Congress may voluntarily remain in session throughout the summer, in order that our Congressmen may be protected from the intolerable discomforts and dangers of the ordinary outdoor weather!”

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

Disks are rolled out onto the south lawn to absorb the impact of Marine One's wheels like giant coffee coasters.

An amazing example of early-20th-century architecture, this church features marble transported from Utah.

When it opened during the final years of the embargo, all the drinks and cigars were free.

A museum that houses the world's largest collection of ventriloquism dummies.

Northern Kentucky’s very own Notre Dame showcases intricate stained glass and the bones of saints.

A 30-foot stack of piano keys memorializes one of the greatest keys players in jazz history.

One of the few beardless depictions of Lincoln, George Grey Barnard's 1917 statue was denounced by many—including Lincoln's own son.

Where beautiful signs live on forever.