https://www.smithsonianmag.com/smart-news/scotlands-tiny-artificial-islands-date-stone-age-180972420/?utm_source=smithsoniantopic&utm_medium=email&utm_campaign=20190623-Weekender&spMailingID=40020199&spUserID=NzQwNDU3MjM2NjYS1&spJobID=1541831047&spReportId=MTU0MTgzMTA0NwS2 Five crannogs in the Outer Hebrides were built 5,000 years ago, perhaps for ritual purposes