READING, ENGLAND—BBC News reports that the mound at Skipsea Castle in East Yorkshire is 2,500 years old. It had been thought that the mound, or motte, which measures 278 feet in diameter and 42 feet tall, was constructed by the Normans in the eleventh century to support a tower surrounded by defensive earthworks known as a bailey. Jim Leary of the University of Reading and his team removed soil samples from the base of the mound and tested charred seeds and pollen. Radiocarbon dates indicate that the mound was already 1,500 years old when the Normans built Skipsea Castle. “It’s the largest Iron Age mound in Britain and there it was hiding from us in plain sight,” Lear said. Further research could reveal how Iron Age Britons used the huge mound. For more on archaeology in England, go to "Legends of Glastonbury Abbey."