"X" marks the spot of an echo chamber in the middle of a plaza.

One of Savannah's oldest and most haunted cemeteries, featuring graves desecrated by Sherman's Union Army.

An Irish Memorial commemorating those who perished due to potato blight.

This elaborate towering structure was once famed for its revolutionary height.

A layered tribute to the work of mosaicist Isaiah Zagar.

The site of Paul Revere's historic two lantern warning.

A former waterfront market is now in the center of town due to some interesting Boston engineering.

A century-old hotspot for jazz, frequented by everyone from Charlie Chaplin to Al Capone.

A six-story treehouse offers spectacular views of New York's Finger Lakes region.

Hollywood's most famous landmark, the "temporary" sign that has stood for decades longer than intended.

A building so large that it has its own weather.

This kitschy tavern is also home to rare early editions of "Treasure Island."

These World War I shooting range tunnels are now haunted halls of underground graffiti accessed through the roots of a tree.

Haunted Victorian house that inspired a legendary "Ghostbusters" court ruling.

Hundreds of numbered stakes hidden in the woods mark the graves of the lost souls of a nearby asylum.

Decades after testing the polio vaccine on unwitting patients, this historic mental hospital sits in ruin.

A terrific purveyor of natural history objects and curios.