An easily overlooked memorial to a Ukrainian famine-genocide that killed over 4 million people.

A celebrity from the late Cretaceous period.

Obscure Freemasons still live in D.C.’s largest private residence.

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

A Spiritualist house of worship where believers communicate with the dead in the spirit world.

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

There’s a hidden military meme engraved on the World War II Memorial.

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

During the Industrial Revolution this “Temple of Invention” was full of intricate miniature machines and gadgets.

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

A painfully obvious spy house sits right across the street from the Russian Embassy.

A wondrous old library overlooking the nation's capital.

There's a 12-foot-tall replica of the Washington Monument hidden under a manhole nearby.

A tiny piece of the Moon is embedded in this stained glass masterpiece.

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

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

The final resting place of the controversial chess champion.

Winding country roads in eastern West Virginia lead to an extraordinary place populated by fiberglass giants.

An eponymous directional signpost erected by the first president of the United States.

Outsider art meets paleontology at this roadside reptile repository.

The Grand Ole Opry's big voice came from a small home in rural Virginia where she was eventually buried.

The only surviving 19th-century water-powered mill found in the Washington, D.C. area.

Collecting 700 years of mechanical death-dealing, the NRA's sprawling gun museum is a revealing testament to the American obsession with armament.

An artsy hidden staircase leads to breathtaking views of San Francisco.