These banned cigarette vending machines now sell little pieces of pocket-sized art.

This grand old 80-foot sequoia towers above the buildings in the city’s retail center.

The last street in Pittsburgh that's paved with wood.

The ruins of Scottish sea salt production.

The shortest river in America flows for just 201 feet.

This abandoned, windowless concrete block is one of the strangest buildings in Tulsa.

The 44,000-ton aircraft carrier was purposely sunk to create an artificial reef teeming with life.

These abandoned grain silos and tunnels are an urban exploration dream.

A cave's rare beauty held a cavernous secret hidden underground.

An abandoned monument remembering the "Pančevo Holocaust" now stands as a shadow of its former self.

This mysterious petroglyph evokes the ancient swastika symbol but was later vandalized with the more troublesome Nazi one.

A perfect circle of 24 mysterious holes dates back to prehistoric times.

Neither Spanish settlers nor anyone since has been able to tell who built these strange California rock walls.

The largest earthwork effigy in the world.

A coastal rock outcrop with mysterious inscriptions variously attributed to Native Americans, Portuguese, Phoenicians, Norse, and more.

Mysterious ancient boulder carved with petroglyphs in the mountains of Western North Carolina.

Native Americans built this circle of stones, which was used to predict astronomical events.

Ancient human, animal, and geometric figures drawn in the earth.

America's oldest archaeological site or a muddled case of wishful thinking.

The state's only comprehensive museum dedicated to the mineral that defined its history and economy.

Once the product of an inexplicable gold strike, this ghost town is now home to one man and his love of classic machines.

This former Indiana quarry has been transformed into a park and SCUBA site where divers can explore the drowned mining equipment.

The highest point in Indiana is curated by an Eagle scout but may be in danger of losing its record to a nearby garbage pile.

One tree's homage to soles past and present.