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Gravity hills, or magnetic hills, are places that look like an upward hill, but actually slope down a little. Gravity hills are optical illusions.
How do gravity hills work?
They all have one thing in common, you cannot see a natural horizon from a gravity hill. Most gravity hills are in forests or areas with high cliffs where the road rises and descends. You can see clearly that the road is not level. But without a reliable reference point such as the horizon, it is difficult for our brains to judge the slopes. They become optical illusions, or more scientifically, cognitive illusions.
Magnetic hills can be dangerous if you leave your car in neutral. You will expect it to stay in place or roll in one direction but actually goes in the opposite direction. There are urban legends about school buses being hit by trains on every gravity hill near a railroad crossing in the USA (Pennsylvania, Oklahoma, Texas, California, and more. Do a Google Search for ‘gravity hill school bus’ and you will find dozens of these stories. None of these stories could ever be verified, though.
Magnetic hills around the world
There are hundreds of gravity hills around the world. Many of the landmarks are turned into tourist attractions, like Magnetic Hill in Ladakh (India), Strange Slope near Shenyang (China), Spook Hill in Florida (USA), and more. Most countries have them.
