Stonehenge was constructed in stages, starting around 2800B.C. It consists of a ring of megaliths surrounded by a bank of dirt and a ditch.Inside the bank of dirt there are many holes. They,too,were dug in a circle.At dawn on Midsummer's Day (usually June 20,21,or22),the sun shines directly though a row of stone monuments.This particular row of megaliths divides the circle of stones directly in half it is the central axis of Stonehenge.The fact intrigues archaeologists because it may show that these early builders knew more about the solar system than historians had previously thought.For them the improthat question remains:How did people of prehistory get so much exact information about the movement of the sun?