This free, take-a-book shop seems like a trick but isn't.

This extraordinary Depression-era expenditure was modeled after a postcard of a Mediterranean hotel.

These tourist trap caverns are said to be the former home of a legendary Pennsylvania Hermit.

Home of the only civilian casualty at the Battle of Gettysburg.

This ruined quarry once produced the distinctive red sandstone used for construction projects in Washington, D.C.

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

Built in the 1850s, this church was of the first five churches constructed in Harper's Ferry.

The last holdout of a pre-Civil War rebel who took the matter of slavery into his own hands.

This advertisement for talcum powder was painted on the rock face and has since defied removal.

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

Bizarre Cavern.

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

A labor of love built by local hang-gliding enthusiasts, this ideal launch spot was outlawed by the authorities and has since been largely abandoned.

Washed out by the Johnstown Flood in 1889, the surviving portion of the original two-span bridge now resides at Fishing Creek.

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

This Maryland farm is known for its amazing corn mazes and its 30-foot junkbots.

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

The smallest covered bridge in Maryland.

This crumbling Death Valley mining complex was known for its use of giant, 20-mule team wagons.

This once-booming Gold Rush town is now home to a herd of feral donkeys.

This immigrant bridge once spanned the Thames but is now a fixture of an Arizona city.

Walk through the actual strap iron cells and solitary chambers of Arizona Territory’s first prison.

The remnants of an early automobile route across shifting sand dunes can still be found in the deserts of Southern California.

This church on a Tohono O'Odham reservation has stood since 1797.