The world's largest mountain carving could fit all of Mount Rushmore inside it many times over.

A monument to the center of the North American continent may be off by a few miles.

Equal parts record-breaking temple to consumerism and bizarre fun park, it's more than you think it is...

Downtown Minneapolis mixed art and function by turning some of their sewer covers into works of art.

A toweringly silly piece of modern art has been delighting locals since the 1980s.

Enter the Forest of the Elves.

A fence constructed completely of skis on Monroe Street.

A treehouse assailed by the elements and the government, now gone.

A six-story-tall golden pyramid, surrounded by a moat.

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

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

Hell on Earth is actually a small town in Michigan where anyone can be mayor for a day.

Glass and concrete building designed by Albert Kahn.

The concrete shell of an industry giant remains as a playground for graffiti artists, auto scrappers, and paintball warriors.

Controversial tribute to the heavyweight champion boxer who grew up in Detroit.

The angel of death appears to weep black tears at this grave marker.

The only presidential monument to display a late POTUS's actual casket.

Gilded heaven for philatelists and architecture freaks, still in full working order despite sitting atop tremulous ground.

The stoutest tree in the world.

An elaborate Mayan city shrouded in alien conspiracy revealed the tomb of Pacal the Great.

Every equinox this Maya pyramid puts on a spooky ancient light show.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

If you can look past the nearby sewer pipes, this urban sinkhole grotto is a mini-paradise.