Archaeologists say the remains of another large henge near the River Avon offer clues to the building of Stonehenge and the significance of the river. They had sought the telltale holes for years. British archaeologists have found the remains of a massive stone henge, or ceremonial circle, that was part of the ancient and celebrated Stonehenge complex, a find that is shedding new light on how the monument was built and its religious uses.