A gravity hill is a place where the layout of the surrounding land produces the optical illusion that the hillside is very little seems to be a hillside. So if we stop the car in the middle of the road and took off the brakes, then, slowly moving his own car would be rolled into an uphill road. If we pour water into the middle of the road, then the water will flow uphill toward the road. It's as if gravity does not work in this place.
If you're curious then come to this place to prove it.
