Crop circles are the patterns produced by the flattening of crops, usually cereals, in a farm or field. Many people believe these crops to be of an extra-terrestrial, or created by obscure natural phenomena. There is, however, no credible evidence to support these claims and the overwhelming opinion is that such creations are of human causation.
Crop circles first appeared in the 1970s and have increased over time. They are usually created overnight so as to avoid detection, and sometimes are made near to important cultural or historical sites, such as Stonehenge, in order to improve the story or effect. Numerous methods are employed in their creation, although the usual method is to use planks of wood and ropes affixed to the centre of the circle.
If you've ever considered making a crop circle then don't: numerous people have been successfully prosecuted for criminal damage to farm property