A mysterious stone embedded at the base of a historic Boston building.

Berthed at the Charlestown Navy Yard in Boston, "Old Ironsides" is the oldest commissioned warship still afloat.

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

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

The Boston square dedicated to the dark poet who was born nearby.

A onetime gangsters' hideaway where you can dine on steaks, fine wines, and cigars just like they once did.

The sign to a demolished amusement park now stands in front of a local library.

Even with its slightly risible name this colossal cross is still able to inspire awe.

This simple gravestone remembers a pig who single-hoofedly raised $19,000,000 for the Navy.

This monolithic statue was erected in honor of Chief Black Hawk (even if it wasn't made to look like him).

Known as the "Cross At The Crossroads," this massive metal cross is just short enough to avoid the FAA.

A towering Art Deco movie palace made to look like a Mayan temple.

One of the few remaining relics of the meatpacking hub that made Chicago the "hog butcher to the world."

The original vault that held the president's remains still stands, empty, not far from where he was finally buried.

It was originally part of a "terrible lizards" collection at the 1964 New York World’s Fair.

This architectural stunner is one of the few surviving Egyptian Revival theaters in the U.S.

Arguably the best example of an authentic Dutch windmill in the United States, rivaling its counterparts in the Netherlands.

Half-sized replica of the Leaning Tower of Pisa built to honor Galileo.

World's second largest particle accelerator, where nature reveals its secrets.

When you visit his grave, be sure to rub the Great Emancipator's nose for good luck.

This modest post office sits on the site of H.H. Holmes' famous murder castle.

What may be America's largest classic video game arcade lurks inconspicuously in a Chicago suburb.

What's left of the ruins of the 1893 Columbian Exhibition, or World's Fair, also known as the White City.

Island where motor vehicles are banned -- home to the only carless highway in the United States.