A historic, scenic mill that was forced to close due to overlogging.

An average of 33 million gallons of water pour out of the collapsed cave at the heart of this spherical spring.

Often referred to as the largest spring in America.

One of the deepest springs in Missouri.

The crumbling remains of the first Black-owned and operated hospital in Kansas City.

An abandoned concrete jungle surrounded by a lush park.

A subterranean haunt where wine and homemade biscottis are always on the menu.

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

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

This former nursery supplied plants for the creation of Chicago's largest park.

This national park dedicated to the tallgrass prairie ecosystem still displays its military past.

What was once the second largest steel mill in the US is now a sprawling complex of modern ruins.

Chicago's North Park Village was once the largest municipal sanatorium in the country.

River pirates, murderous bandits, and serial killers used this Illinois cave as their debauched hideout.

These abandoned grain silos and tunnels are an urban exploration dream.

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

Thousands of bottles that have held everything from poison to perfume make up the collection of this small museum.

The remains of a large iron mill that once stood in the remote woods of northern Maine.

A 60-foot-tall tower provides unparalleled views of the southern Green Mountains.

Designed as a place for patients to take in the scenery, this tower has a dark history.

The building that inspired Shirley Jackson's "The Haunting of Hill House."

Tour the world's largest deep-hole dimension granite quarry, where you can view the plant where gravestones are made and roll a ball down the outdoor granite bowling alley.

An abandoned Victorian-era mill in the middle of modern Manchester.

An abandoned 146-acre summer resort slowly being reclaimed by nature.