Remnants of a storybook amusement park hidden behind a strip mall.

The only National Monument ever to go missing for nearly 50 years then resurface in a dump.

Seemingly unremarkable items like empty sushi trays, chef hats, and freshness stickers are being preserved so future generations can look back on this beloved cultural import.

An overlooked oasis of quiet on the grounds of Washington's monumental basilica.

Perhaps the most scandalous statue of America's first president.

This taxidermy horse was a Civil War hero.

Largest Roman Catholic church in North America.

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

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

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

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

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

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

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

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

Rumor has it the hot dog stand was targeted by two Russian nuclear missiles.

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

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

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

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

A cavernous three-story, 43,800-square-foot basement that was forgotten about for 60 years.

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

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

A haunting tribute to pioneering photographer Clover Adams.