Relatively Recent Phenomenon

(Image credit: winjohn | sxc.hu)Crop circles first began cropping up in the 1970s, sparking claims that they were created by extraterrestrials. Although two men came forward in 1991 and said that they had created the patterns as a UFO hoax, they didn’t take responsibility for all of the crop circles, leading some people to believe that perhaps something paranormal is also responsible for the strange spheres. While scientists know paranormal forces have nothing to do with crop circles, the patterns are intriguing, with some scientists trying to figure out exactly how they are made.

Castle Crop Circle

(Image credit: Travelmax | Dreamstime)Here, an intricate crop circle that appeared in front of the Torrechiara Castle in Parma, Italy, during the summer of 2009.

View from Within

(Image credit: qr5 | sxc.hu)Baffled bystanders explore a crop circle found in the agricultural community of Hensall in Ontario, Canada. The circle appeared in 2003, and no other crop circles have occurred in the area since.

Triskelion Disk

(Image credit: Handy Marks | public domain)This massive 780-foot (238 meters) crop circle appeared in 2001 in the remote area of Milk Hill in Wiltshire, England. The elaborate design is composed of 409 circles that form a pattern called a double, or six-sided, triskelion, which is a motif consisting of three interlocking spirals.

Crop Circle in Germany

(Image credit: Klaus Leidorf)An aerial view of a crop circle near Starnberg in southern Bavaria, Germany, taken on Aug. 9, 2006.

Sutton Bank Crop Circle

(Image credit: Ash Balderson)A crop circle located near the hills of Sutton Bank in North Yorkshire, England. This aerial shot was taken on July 9, 2010, and the photographer, Ash Balderson, told LiveScience that the pattern was made over the weekend of July 3 and 4, 2010. The view is from the top of Sutton Bank, looking back down into the valley.

Wheels Within Wheels

(Image credit: Ash Balderson)The crop circle of Sutton Bank in North Yorkshire, England, seen from a different angle.

Golden Globes

(Image credit: Jabberocky | public domain)People inspect crop circles within a golden wheat field in Switzerland. The photo was taken on July 29, 2007.

Corn Flower

(Image credit: Hansueli Krapf)This blossom-shaped crop circle appeared in June 2008 in Diessenhofen, Switzerland.

Triskelion Crop Circle

(Image credit: Thomas J. Sutter, Jr. | public domain)Another triskelion crop circle. The symbol can be used to represent cycles, progress or competition.

For the Birds

(Image credit: public domain)This design of three flying birds was created on Aug. 3, 2003, in the county of Wiltshire in southern England. The birds, which resemble swallows, have ever-diminishing circles trailing behind their wing tips.