On a typically misty morning in the west of Ireland, just outside the medieval town of Athenry, County Galway, archaeologist Declan Moore... is taking me to visit an unexcavated fulacht fiadh (pronounced FULL-ahk FEE-add), or fulachtaí fia in plural, the most common type of prehistoric archaeological site in Ireland. Better known as a "burnt mound" in the neighboring United Kingdom, where they are also found, there are nearly 6,000 recorded fulacht fiadh sites dotted around Ireland alone... When we arrive at the site, Moore shows me the basic features of a fulacht fiadh -- a horseshoe-shaped mound of soil and...