A Crop Circle is a geometric pattern. They appear in fields, usually wheat, grass or oats fields and frequently in England. Crop circles existed in the thirteenth century, such as the construction of Stonehenge and Hadrian's wall between England and Scotland.
It's only flattened corn... Doug Bower, 1991.
Some believe that the crop designs are messages from alien spacecraft. Some maintain that the aliens are trying to communicate with us using ancient Sumerian symbols or symbolic representations of alien DNA. Those who engage in such serious study and theorizing about crop circles are known as cerealogists (after Ceres, the Roman goddess of agriculture and fertility) or croppies.