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

Mural made of 100,000 pieces of hand blown glass, and until recently, the largest glass mural in the US.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

A layered tribute to the work of mosaicist Isaiah Zagar.

World's first "penitentiary," meant to be humane, drove men insane.

A once-booming Mississippi River town with a history of racial violence is now eerie and mostly abandoned.

Four glass boxes hover over 1,000 feet in the air to give visitors an unparalleled view of Chicago.

This morbid, delightful curiosity shop offers everything from animal bones to human teeth.

This shop for all your super spy needs hides an educational secret.

This massive stained-glass masterpiece is thought to be the largest Tiffany dome in existence.

A 35-foot-tall fork stuck in the ground outside an office building in Missouri.

A creepy sculpture of a decapitated head invites viewers to see St. Louis through its empty eyes.

The "World's Largest Underground Business Complex," a 55,000,000-square-foot city underneath Missouri.

Curious cave that stays a cool 56 degrees all year long.

The world's largest man-made underground caverns offer unparalleled underwater wonders.

The history of the treatment of mental illness, illustrated in all its gory detail, and housed in an asylum.

This abandoned prison castle has become an imposing gallery of graffiti art.

Once an ambitious nature spa, these forest ruins now provide a serene monument to failure.

European castle ruins in an American state park are actually the product of death and grief.

Less a museum than a bizarre fantasy world created by artists and engineers.

It's big, it's a ball, and it's made of twine—the world's largest of its kind.

A whimsical monument marks the highest point in Kansas, not that you could tell by the looks of it.

During the 1990's nearly all of the world's LSD is thought to have come from the operators of the lab once located in this missile silo.

The United States's largest hand-dug well is topped with a state-of-the-art museum.