This unique historical monument features large concrete spheres designed to resemble fallen stars.

A secretive collection featuring objects that were designed specifically for U.S. intelligence operations.

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

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

This mighty white oak in Bethesda survived both the American Revolution and the construction of Washington D.C.'s metro red line.

A haunting tribute to pioneering photographer Clover Adams.

An Industrial Revolution-era public work that purified water using nothing but sand.

An intricately designed junk art house with four extravagant junk art cars hidden in the suburbs.

The United States Capitol's former columns still stand.

Rumor has it the uncarved lump behind the three famous suffragists is reserved for the first woman president.

Home to items never before seen by the public.

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

A replica of the famous memorial statue at the Normandy American Cemetery hides in an office building in downtown D.C.

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

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

Soldiers were buried next to Lee's house in the center of Arlington Cemetery to dissuade the general from reclaiming his property after the war.

A gift from Scotland to the United States in memory of the 270 lives lost when Pan Am Flight 103 exploded over Lockerbie due to a terrorist bombing.

In what is rumored to be an intentional act of spite, this memorial almost completely obscures the nearby grave of a senior officer.

The rogue roots are gradually consuming some of the historic marble grave markers.

An oft-overlooked, magically musical monolith that stands majestically between Arlington Cemetery and the Iwo Jima Memorial.

An extensive, if one-sided, history of U.S. law enforcement's war on drugs.

A castle built by an eccentric medieval enthusiast in rural Ohio.

Inside, ancient treasures. Outside, modern contradictions.

Where beautiful signs live on forever.