This Saturday, Aug. 22 is the grand opening of the Explorium at the Horicon Marsh Education and Visitor center. The event runs from 10 a.m. to 5 p.m. at Horicon Marsh Wildlife Area off of Highway 28 between Horicon and Mayville. The day will feature tours of the new Explorium, opportunities for hands-on science in the center's learning lab, guided hikes with wildlife biologists and more. Visitors to the center will find a charging woolly mammoth, walk-through glacier, an airboat simulator ride and a giant great blue heron replica