Conflicting markers on its floor tell a tale of two city centers in San Antonio.

The headquarters of a secretive order is also a beautifully-designed park.

Elevated freight railway turned wildly successful urban park.

This ancient octopus-like tree was saved from destruction thanks to shady reporting.

A monument to a Polish general who fought the American Revolution and became the "Father of the American Cavalry."

A 19th-century architectural wonder designed by the "father of the skyscraper."

The seat of Buffalo government is a gorgeous Art Deco palace.

The artwork commemorates the many ways 20th-century people perished while on the clock.

A 98-room castle in the middle of Toronto that bankrupted a 19th century electricity multimillionaire.

Buffalo's abandoned concrete grain elevators are getting a second life.

Recognized the world over as the home of the McCallisters in the 1990 movie "Home Alone."

The site of the first couple's first kiss is commemorated by the most adorable presidential monument ever.

This abstract sculpture is rumored to cast a hammer-and-sickle shadow once a year.

This bronze sculpture on a former squash court marks the secret origins of the Atomic Age.

One of the largest pieces of scientific equipment ever carried on a NASA space shuttle sits in a Chicago alley.

An actual 1957 Cadillac De Ville, encased in 15 cubic yards of concrete.

A strange rock in Chicago marks the spot where a tree once stood in honor of the 18th President.

A hollow cement depiction of time's inexorable effect on the human body.

Housed in a memorial lighthouse, this museum relays the history of surfing, beginning with the antics of royal Hawaiian teenagers.

A strange house built only at night, with rumored mystic inspiration.

The grave of America's 11th president is not in some grand monument but instead it's hidden away on the grounds of the Tennessee Capital.

One incredible room in the Santa Barbara Courthouse is covered in wall-to-wall canvas murals.

Colorful sand dunes create a unique attraction in this part of Utah's red-rock country.

Rippling sand dunes frozen in the Arizona rock.