Stonehenge in Wiltshire

You're standing at Stonehenge, on Salisbury Plain in Wiltshire, England. In front of you is one of the most famous prehistoric sites on Earth. Start with the outer ring. Those upright stones are about four metres tall and weigh roughly twenty-five tons each. Across the top lie lintels, fixed with mortise and tenon joints, the way a carpenter joins wood. No other monument of that age has them.