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.

The Cold War-era "underground Pentagon" is a sprawling subterranean hideaway for the Defense Department.

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

According to local history, this cast-iron canine was nearly melted down for bullets during the Civil War.

This hidden treasure provides a charming access point along the south side of Baker Park.

This four-story steel sphere in Maryland was used to test biological weapons.

A well-preserved quarry and six of eight continuous burning pot kilns used to make burnt lime and crushed stone are highlights of the self-guided walking tour in Fountain Rock Park.

Take a trip to the past aboard a 1920s railcar or open flatcar for a scenic ride through Maryland farm country.

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

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

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

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

The smallest covered bridge in Maryland.

Knoxville’s architectural icon was the symbol of the 1982 World’s Fair, even catching the googly eye of Bart Simpson.

Before TV meteorologists, there were weather kiosks. This may be the last one in the United States.

This chestnut box will not be opened until the country music legend's 100th birthday in 2046.

Mile-long cave system near Great Smoky Mountains.

This ornate Victorian marketplace was the setting for Diagon Alley and the Leaky Cauldron in the first ‘Harry Potter’ film.

Catacombs turned marketplace.

This medieval sanctuary's tree-framed door looks like a portal to a mythical realm.