A bronze plaque marks the site of the only show the "King of the Soul Singers" ever missed.

The birthplace of a titan of American cinema.

This solitary gravestone is separated from the rest in Appleton, explaining why local legends continue to surround it.

Giant six-pack could provide one person a six-pack a day for 3,351 years.

The bugs crawling down the front of this office building are almost as big as a '68 VW Beetle.

Statue dedicated to the star of an old television show.

Every drop of D.C. tap water flows through this old waterworks.

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

A computer bug so primitive it was an actual insect.

The walls of the iconic dome are hollow and have a secret stairway.

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

This leafy estate is worth $18 million and is so grand it has two mailing addresses.

Four bald cypress trees in Lafayette Square, across from the White House, mark the southern edge of a 100,000 year old cypress swamp.

The country's oldest continually-operated mini golf course lies hidden in plain sight, eclipsed by one of D.C.'s most popular tourist attractions.

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

This claimant to the title of "smallest church in the 48 states" doubles as an equally tiny, quasi-post office.

A memorial in coal country commemorates the victims of an all-too-preventable mining disaster.

A humble plaque marks the site where the country music legend was found dead in his Cadillac.

This abandoned dream castle and its cemetery look out over the city that once inspired their creation.

The world's largest fully steerable radio telescope.

One day a year it is legal to jump off of this astoundingly tall bridge that spans an Appalachian gorge.

The "mysteries" of this quintessential roadside oddity were almost destroyed by neglect but were saved by fans of kitschy wonder.

This red-eyed chrome beast pays homage to the popular modern myth of West Virginia's insectoid monster.

America's post-nuclear-attack chambers of Congress.