Every gravestone tells a story, and on Sunday, Brenda Sullivan of the Gravestone Girls will give a lecture and slideshow presentation uncovering some of the mystery and symbolism carved into the stones marking where locals were buried in town. “There’s a treasure trove of history right in your backyard,” Sullivan said. “I consider it my job to get people out into the cemeteries.” The Gravestone Girls is a company promoting cemetery awareness as a way to look at a town’s history through the people who lived there. They are particularly interested in understanding the imagery on early graves. Sullivan’s presentation begins at 2 p.m. at the Hopkinton Historical Society, at 168 Hayden Rowe St. It is free to the public and refreshments will be served. No reservations or tickets are needed. - Ellen Ishkanian