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

A pre-Industrial Age iron furnace and the site of a nearly-forgotten piece of Black history.

A giant time capsule not scheduled to be cored until 2040.

Once the home of a noted Civil War spy, the two-story brick house now serves as a museum.

This giant, rotating globe was built to celebrate the expansion of a company that makes steam cleaners and pressure washers.

Built in the 1970s, this curious modular home found new life as a sundae-shaped ice cream stand.

Bizarre Cavern.

Built by the patriotic residents of Boonsboro in a single day.

This museum explores the grim reality of life in the earliest British colonies in America.

The land is home to swimming ponies and a legendary 18th-century treasure.

The grounds of former plantations where abolitionist Harriet Tubman spent her youth enslaved are now a museum to her incredible life.

This awkward aquarium sculpture is one of the strangest statues in Chicago.

A chilling disappearance (and rescue) of a child uncovers a geological mystery.

A star fort along the C&O Canal in western Maryland that protected America in three wars.

Once damaged by Hurricane Agnes, this bridge is now on the National Register of Historic Places.

This propitious plastic porcine has been petitioning park visitors to pick up after themselves for more than 50 years.

This fort down the Potomac from Washington, D.C. was once the only defensive fort protecting the capital.

A girls' boarding school inspired by the Chicago World's Fair, once abandoned, now restored to strange and scenic glory.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.

These unusual rooms on wheels are holdovers from the 1960s.

An almost life-sized elephant named Ms. Ellie greets visitors at this jumbo-themed museum.

This shale formation along the Appalachian Trail once inspired the third president of the United States.

First built around 1848, this bridge was destroyed by arson, but original timbers are included in the replacement.

One of the only memorials dedicated to journalists who died in combat.