Forget wheels. What if you sat inside one and let it roll?

The monowheel has been thrilling (and terrifying) riders since 1869.

Imagine a wheel. Now imagine sitting inside it, astride a small engine, and letting the whole thing roll you down the road at nearly sixty miles per hour. That’s the monowheel—a vehicle that looks like something from a steampunk fever dream. The concept dates back to 1869, when the first designs appeared, and it has never stopped capturing imaginations. The engine, similar to a motorcycle’s, revolves the outer wheel around the rider, who sits suspended in the center. The current world record stands at sixty-one miles per hour, though reaching that speed requires nerves of steel and a complete disregard for conventional vehicle stability.

There are reasons you don’t see monowheels at your local dealership. Steering and braking are, to put it mildly, challenging. Riders often use their feet to help turn or stop, which is exactly as terrifying as it sounds. The physics are inherently unstable: when you accelerate, the rider inside tends to swing forward; when you brake, you swing back. Cornering involves leaning, which the monowheel resists with every gyroscopic principle it violates. Yet the idea persists, appearing everywhere from vintage patents to science fiction, and occasionally at exhibitions where someone is willing to risk a few bruises for the spectacle. It’s not practical transport. It’s barely safe. But a hundred and fifty years later, we’re still dreaming about sitting inside the wheel.