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.

Herbert Hoover's "Brown House" rural presidential retreat was a PR disaster amid the start of the Great Depression.

Lines from a walking song are etched into a rock in Natural Bridge State Park.

Inspired by a foil-wrapped potato, (seriously) the Markel Building has been deemed one of the 10 ugliest buildings in the world.

This collection of over 50 classic pinball machines awaits visitors to downtown Roanoke.

This maze-like slot canyon is a unique gem within an already fascinating geological area.

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

Exact replica of the ancient monument, but much, much lighter.

America's original house of worship for Spiritualism, the religious movement based on communing with the dead.

"the sweltering inhabitants of Charleston and New Orleans, of Madras and Bombay and Calcutta, drink at my well . . . The pure Walden water is mingled with the sacred water of the Ganges."

Inspiring Herman Melville and Henry David Thoreau, Mount Greylock in western Massachusetts is the highest point in the state at 3,491 feet above sea level.

A cave dug by a man directed by ghosts to find pirate treasure.

The walkable ruins of an 19th century hotel, destroyed in a horse cremation gone wrong.

This pre-Revolutionary War grist mill ground corn and flour for soldiers in seven American wars.

Parking garage where Bob Woodward met Watergate source "Deep Throat."

This once-palatial plantation may have been the site where a draft of the Declaration of Independence was written.

A secretive collection featuring objects that were designed specifically for U.S. intelligence operations.

A 300-yard long natural tunnel runs through a ridge deep in the Appalachian Mountains.

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

A sacred site for Native Americans surveyed by George Washington and owned by both King George III and Thomas Jefferson.

A fully functional, 200-year-old remnant of the time when Brixton was mostly fields.

Tombstones and enigmatic inscriptions hide within a vault beneath a popular London arts venue.

A network of concealed passageways lies within a busy London Underground station.

Following the trail of an old metro line, this scenic path is haunted by a creepy spriggan statue.