A bas relief commemorates the "Nuns of the Battlefield" who cared for soldiers on both sides of the conflict.

The most accurate timepiece in the world.

The bridge's highly-contested plaque (once again) honors Confederate President Jefferson Davis.

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

Berkeley Hot Springs presents to you "the only outdoor monument to presidential bathing."

A star fort along the C&O Canal in western Maryland that protected America in three wars.

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

A Civil War fort in the middle of Washington, D.C. has been swallowed by a forest.

Enormous piles of historically significant stones, dumped by Congress in a forest, and abandoned for 60 years.

Washington's top-secret Cold War-era doomsday communications tower is located in a small neighborhood park.

The only Civil War battle in Washington D.C. took place near this highest natural point in the city.

The beloved statue at the National Academy of Sciences is oh so inviting to sit on.

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

The bank that helped fund the Mexican-American War and the purchase of Alaska met its downfall after helping Augusto Pinochet launder money.

A monument in Washington D.C. marks the spot from which all other roads were supposed to stem.

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

Housing the National Women's Party since 1929, this historic house is now a monument to the fight for gender equality.

A 19th-century Gothic, castle-like statehouse by the Mississippi River.

This racially troublesome eatery thought a new coat of paint could erase its offensive connotations.

A grandiose octagonal home crowned by a large dome stands out among the antebellum mansions.

The LSU mascot lived on the college campus in one of the most impressive tiger habitats in the country.

This campus chapel is Robert E. Lee's final resting place and a topic of debate about the legacy of the Civil War.

One of the last active volcanoes on the Eastern seaboard.

"We Seceded Where Others Failed."