Updated from original post August 2017
The jury is still out on how these wonders of nature come about, a mystique that only adds to our sense of wonder. I chanced upon a spectacular crop circle at Cley Hill near Warminster - the first I have seen at close range and was struck by its perfect symmetry and majesty. It prompted me to look into the phenomenon.
This was a chance meeting. After ascending the steep path to the top of Cley Hill, which overlooks Warminster, Longleatand Frome, my eyes were opened for the first time to the wonders of the spectacular crop circle - this one in the adjoining field to the east of the hill.
Cley Hill is a prominent hill to the west of Warminster in Wiltshire (seemingly the capital of crop-circles in England). The land is in Corseley parish and is owned by the National Trust. Wikipedia reports that there is a legend that the hill was formed by the devil, when he dropped a sack of earth with which he had planned to bury the town of Devizes. He had retrieved the earth from Somerset and was travelling to Devizes when he stopped to ask an old man the distance to the town. The man replied that he had been walking for years to reach Devizes, so the devil abandoned his plan
Rather than speculate or add to the huge amount of words already written, have a look at crop circle connector's FAQs page - interesting reading http://www.cropcircleconnector.com/anasazi/faq98.html
The whole site is a very useful resource.
Photo courtesy Hugh Newman
This video takes you a close-up tour of the crop circle in all its glory