There is a section of upper Parel Vallei road that is known as Spook Hill. On this section of the road it appears as if downhill actually is uphill and vice versa. It's an optical illusion. But if you see that cars roll uphill here (and that's a fact), it generates discussion if this is an optical illusion, magnetism or one of the world’s great unsolved mysteries. You can watch or try this in front of Straightway Head Country House, at the top of the Parel Vallei Road.