Gravity Hill
A gravity hill, also known as a magnetic hill (and sometimes a mystery hill or a gravity road), is a place where the layout of the surrounding land produces the optical illusion that a very slight downhill slope appears to be an uphill slope. Thus, a car left out of gear will appear to be rolling uphill due to gravity.[1]There are hundreds of gravity hill locations around the world. See list of magnetic hills.
http://en.wikipedia.org/wiki/
