A gravity hill is a place where gravity seems to be working against itself; where gravity seems to temporarily not work as it should. There are hundreds of gravity hills around the world and they are characterized as places where a geographical optical illusion has been created.
Gravity hills are, at their core, an optical illusion. The landscape of an area can make a small downhill slope appear to be going uphill. Cars can be seen rolling uphill against the perceived gradient of the road, stunning drivers and spectators alike. One of the most important feature of a gravity hill is that the horizon line is partially or completely obscured, which blurs viewers’ perception of up and down.
Some gravity hills are reported to not just be optical illusions, but sites of supernatural activity as well. Most of these are local myths and legends, but guides and fans of the local spots swear by their tales. California, to name just one location of mystery spots and gravity hills, is chock full of anomalies ranging from old mining roads to the Golden Gate Bridge. One particular mystery spot has been attracting visitors since the 1930s and is the site of more than a few eerie feelings and misunderstood sightings.
Scientists will point to the facts when observing gravity hills- you can’t see the horizon, the trees are bent in a different manner, the gradient of the road is offset by the geography of the surrounding hills. Our human perceptions are often not enough to discern what is right in front of us; our brains take in so much information and, in the process of filtering some of it out, makes us see things.
The wonder of gravity hills shouldn’t be taken away by science, though. People around the United States and the world continue to marvel at their car parked in neutral rolling up what seems to be a downhill slope. People will pay to stand in line and experience the weirdness surrounding the Mystery Spot in California, while others will marvel at the stream that seems to be flowing uphill.