Stonehenge （巨石陣）is probably the most famous prehistoric structure in England. It is a collection of enormous rectangular stones arranged in a circle in an open field south of London. Archeologists say that Stonehenge was built over 5000 years ago, made up of 800 gigantic rocks. Some weigh more than two African elephants put together. To this day, historians still don’t know how the rocks were moved there. There were no trucks, cranes (起重機）available 5000 years ago to transport the enormous rocks to the field. Geologists believe most of the rocks are from a quarry（採石場） 200 miles away. Recently they discovered one of them is actually transported from Scotland, which is 400 miles away. Historians think whoever built it probably moved the rocks over water, be it by the sea or the ocean. It’s the most probable explanation.