Although many crop circles are man made, they are more than just rural graffiti. When the patterns of them are actually studied they represent physical structures that we are only now beginning to recognise as a higher understanding of science. They have been recorded for centuries and often are in locations where UFO activity is frequent. Often the crops that have been crushed will exhibit signs of microwave exposure which turns the plant's internal water into steam causing them to either expand or burst and leaving them dried out which is a sign that it may not just be rebels trampling psychedelic patterns into farmer's fields. These enormous and intricate formations seem to appear with no trace whatsoever, in time frames that would be impossible to create using just a few people. Much like the pyramids which some believe the Egyptians constructed with the help of a higher life form, these anomalies remain a mystery.
The following video is a deeper look into this phenomenon: