Gravity Hills

A gravity hill, or a magnetic hill as they are sometimes called, are hills or terrain slopes where it is claimed that magnetism (or some other supernatural power) causes cars or other wheeled vehicles to seemingly roll uphill. There are hundreds of gravity hill locations around the world including several here in New Jersey. One in Titusville, one in Jackson, and one in Franklin Lakes. But what causes this phenomenon to occur?
Sadly, there is a logical explanation for gravity hills. While magnetism could potentially be a scientific explanation, it is not the case here. As it turns out, it is all just an illusion or a trick of perspective and perception. This is caused mainly by an obscured horizon. Without an obvious horizon as a reference point it is difficult to judge the slope of a surface. Also, features of the landscape such as leaning trees can offset your visual reference causing the seemingly gravity defying feat.
Here is a video of one in action.