Giant busts of 42 U.S. presidents are sitting in a field in Virginia.

An abandoned asylum once on the cutting edge of lobotomies may be reborn as a Christian college.

The abandoned grounds and derelict greenhouses of this once-magnificent Edwardian estate are now a nature preserve open for exploration.

This natural rock "church" might not be a proper chapel but that doesn't mean it's not beautiful.

This once sprawling resort now sits abandoned, filled with graffiti and vibrant colors from an era long passed.

Possibly the smallest church in the world floats in the middle of a pond.

These conical kilns measure an impressive 30 feet in diameter, and were once used to produce charcoal for a local blast furnace.

A former Canadian automobile ferry mysteriously appeared in the Black River 20 years ago, and now it quietly rusts away.

This former mill tunnel was blasted under the ridge to divert a portion of the Muscatatuck River.

Three bridges straddle a stream, one stacked upon the other.

This elaborate tunnel is the first structure composed of cast concrete in the United States.

This unique structure is the only one of its kind in Virginia.

This tiny 19th-century tunnel was built so a man could move his cows from one field to another.

This railroad tunnel was once the longest in Massachusetts.

The railroad tunnel nicknamed the "Bloody Pit" for taking the lives of hundreds during its construction.

An innovative attempt to break a siege in the American Civil War still scars the earth today.

A railroad tunnel that, upon its completion, was considered one of the engineering marvels of the modern world.

This brick-lined pedestrian walkway was once a railway tunnel used during the Civil War.

This little brick tunnel built by Confederate forces was used to conduct surprise attacks on the railroad.

Once a sewer culvert, this road tunnel now offers cyclists and pedestrians a subterranean stroll under the C&O Canal.

A piece of crumbling highway infrastructure was repurposed as a high-tech facility for testing racecars.

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

An abandoned railroad tunnel forgotten by time awaits inquisitive hikers.

Locals dubbed this abandoned abode the "gingerbread house" because of its odd architecture.