Caelum Incognitum — The interactive encyclopedia of ufology
Crop circles
Objects & phenomena
Geometric patterns formed by flattened plants in fields, which appeared in large numbers in southern England from the 1970s-1980s and grew more complex in the 1990s. In 1991 Doug Bower and Dave Chorley admitted to making many using planks and ropes; groups of artists now create them on commission.