The Aurora Historical Society is opening the doors at four East Aurora historic sites for special tours beginning this Saturday and running through May 19.Open house-style tours at 2 p.m. Tuesdays through Sundays in that three-week span will be offered at the National Landmark Millard Fillmore House Museum, the Elbert Hubbard-Roycroft Museum and the Tiffany windows at Baker Memorial United Methodist Church.