The sixth annual National Walk @ Lunch Day, sponsored by Blue Cross and Blue Shield companies to promote the health benefits of walking and regular exercise, will be held on Wednesday, April 25. S.C. BlueCross will hold a community walk from 11 a.m. until 2 p.m. at Marion Square in Charleston. The event is free of charge and open to the public. It will include a walking course, health and fitness information, entertainment and giveaways.