The Walker School has purchased 18 acres for $4.6 million to expand its campus from 32 to 50 acres at 700 Cobb Parkway, Marietta. The school will develop property adjacent to the school for athletics. Head of School Jack Hall said the addition will allow the school to add four athletic fields contiguous to the baseball field and flexibility to upgrade and redefine existing academic and fine arts facilities. The school has 980 students in pre-k through high school.