Stonehenge, the greatest and best preserved of the stone circles (q. v.) of Britain, situated in Salisbury Plain, Wiltshire, 7 m. N. of Salisbury; "consists of two concentric circles, enclosing two ellipses"; the diameter of the space enclosed is 100 ft.; the stones are from 13 ft. to 28 ft. high; is generally regarded as an exceptional development of the ordinary stone circle, but the special purpose of its unusual construction is still a matter of uncertainty.