Stonehenge is arguably the greatest prehistoric monument in western Europe; as a World Heritage Site it ranks in significance with such sites as the Acropolis of Athens, the Pyramids of Giza, Great Zimbabwe and Machu Picchu. Stonehenge sits at the heart of a landscape rich in other monuments and remains of the Neolithic period and Bronze Age that are also part of the World Heritage Site. Recent research by English Heritage's landscape archaeologists...