This is Gravity Hill in Helena. In the foreground is Sulphur Springs Road. Crossing our view left-to-right just beyond the little white car is highway 49.
It's one of those "cars rolling uphill" illusions that crops up from time to time on America's road system. This isn't the most spectacular of such illusions, but it does work and it doesn't cost much to give it a try.
So here's how to get the most out of the illusion. Get on Sulphur Springs Road at route 185 and head north. When you top the hill you'll be looking downhill at the intersection just like in the photograph. Drive to the stop sign and put your car in neutral. You'll start rolling backwards up the hill about fifty yards or so to just about where that little white car is.
At right is a map to the mystery. Downtown Helena is in the lower right hand corner of the map.