A colorful piece of contemporary art cheerfully clashes with Lyon's historical architecture.

This ancient theater was once the home of fierce gladiatorial battles.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

The lost Latin words were reconstructed using the holes from the nails that once pinned them in place.

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

A terrace reminiscent of Rome's Spanish Steps is tucked away in a little park in Washington, D.C.

A gift from Japan, 17th-century lantern stands among the cherry trees at D.C.'s Tidal Basin.

Now a living classroom, this house was once the home of Reverend James Clinton Dent, a formerly enslaved man and a pastor.

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.

One of the three perfect vellum copies of this historic book known to exist is on display in a specially-designed case.

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

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

This statue of one of baseball’s greatest pitchers looks like something out of a sci-fi horror movie.

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

Part of a WWII submarine is lurking outside the Washington Navy Yard parking lot.

A derelict bit of infrastructure from the canal that once ran through D.C. is landlocked in the heart of the city.

The National Park Service’s best-kept secret with views that rival any in D.C.

A tiny monument to the unsuccessful attempt by Thomas Jefferson to place the prime meridian in Washington.

Art deco landmark on the outskirts of Washington, D.C.

An overlooked memorial honoring the local Washington residents who died in World War I.

This unassuming passageway played a key role in one of the most important events in U.S. history.

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

An unassuming, powerful monument north of the U.S. Capitol bears witness to the resilience of Japanese Americans during a time of grave injustice.

The preamble to the U.S. Constitution written entirely from vanity license plates hangs in the Smithsonian museum.