Gravity Hill
A gravity hill is a magical place where the landscape tricks your eyes, making a gentle downhill slope seem like it's going uphill. So, if you leave a car out of gear, it looks like it’s defying gravity and rolling uphill! This quirky phenomenon is all explained in this fun Wikipedia article.
#6 Actually a really cool list
#19 I remember when I first found out that the Roman statues used to be paint to make them appear lifelike. Creepy.