Consisting of concentric circles of stone surrounded by a moat (called a "henge"), Stonehenge was constructed in several stages over thousands of years.
Bombproof -A hold or anchor that is thought to offer the utmost security; for example, a top-rope anchor around a large, stable tree trunk or immovable boulder.
But their surfaces bear witness to homely labor: Topping the tallest stone, once part of a trilithon, is a tenon—half of a mortise-and-tenon joint borrowed from woodworking.
The original Mangonel was first used in Roman times to fling large rocks at enemies.This Mangonel, though bearing some resemblance to its forebear, is far larger than its Roman counterparts.
Another form is the menhir, a simple upright stone usually placed with others to form a circle, as at Stonehenge and Avebury in England, or a straight alignment, as at Carnac in France.