You could be standing at the site of one of D.C.'s most fatal tragedies and not even know it.

This lonely waterfront memorial to the men of the Titanic was erected by the "Women of America."

Long-abandoned trolley tunnels just a mile away from the White House are turning into an art space.

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

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.

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

There’s a special club house at the top for the bell ringers.

The sci-fi villain is a little-known inhabitant of the U.S. capital's largest cathedral.

During prohibition, corrupt city officials ran drinking dens under the streets of Downtown Los Angeles.

The spectacular collection of one of the world's best woodcarvers.

Penn State's giant bug collection.

This 19th century machine put animals (including humans) in boxes to study how they metabolized calories.

No one knows who painted this mysterious mural in a Penn State basement.

The 25th President's marble casket can be visited in this classical Ohio tomb.

Mausoleums, astronomy, and animatronic dinosaurs at this memorial to an assassinated American president.

Despite violent work crews and massive delays this abandoned canal tunnel was built to last into the modern day.

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

"Where the ducks walk on fish."

An abandoned stretch of highway, deteriorating next to the operational one.

A grandiose title could not save this mercantile community from obscurity.

The site of Neil Armstrong's first flight is marked by a full on replica of the moon landers.

Behold the rickety wooden glory of the world's oldest operating roller coaster.

This alley-cum-fan gallery in the ex-Nirvana drummer's hometown holds the world's largest drumsticks.

The site of America's first commercial oil well essentially disappeared after the town went bust.