The apparent chronology of the construction of Avebury is counterintuitive, with the inner circles seeming to have been erected first, around 3000 BCE, followed by the protective earthworks, which are some 380 yards (350 m) in diameter. The final major work was the outer circle of standing stones rimming the inner perimeter of the earthworks. There were originally four entrance portals framed by giant standing stones. The inner circles appear to have had some ceremonial significance: the northern circle housed the Cove, a horseshoe shaped stone formation opening (roughly) towards midsummer sunrise. All the stones at Avebury are locally sourced and unfinished, unlike Stonehenge 17 miles (27 km) to the south. The southern circle originally had an obelisk at its centre and a stone with a ring aperture on its southern edge: these, and other stones, were demolished/removed in historic times, by locals either looking for building materials or offended by their pagan symbolism.
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