A wondrous old library overlooking the nation's capital.

The site of the climactic scene from the classic horror film is now a historic landmark.

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

The first memorial dedicated solely to the Black troops who fought for the Union.

The first purpose-built art gallery in the United States is once again open as a center of craft arts.

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

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

The monument's pointy aluminum tip has been melted down by repeated lightning strikes.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

Was there a small "backpack nuke" hidden in the attic? JFK apparently thought so.

The sculptor was instructed to add “stallion attributes” to the general's bronze mare.

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

After James Madison's death, his wife and former First Lady Dolley Madison lived in this yellow building near the White House.

The winding route passes through an enclosed alleyway, two tunnels, and leads to the White House basement.

D.C. once had its own tiny rival to the New York Stock Exchange.

The house where John Wilkes Booth conspired with his co-conspirators.

The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

The 28,000-year-old specimen is remarkably intact.

One of the most influential presidents in U.S. history wanted only this plain, elegant monument as his lasting memorial.

A spectacular tribute to statesman and philanthropist Andrew Mellon.

A muscular Art Deco monument represents the struggle between regulators and unbridled markets.

A three-story tower of books about Abraham Lincoln is one of the more unusual monuments to the president.

Light bulbs, scrap wood, and tinfoil comprise this homemade throne of the gods.

Go take a picture with the inventor of the daguerreotype photographic process.