beginning to wind down. crews are shifting from rescue to recovery. we also have learned that this was an ef-5 tornado. that is one of the most powerful tornadoes ever recorded, packing winds of up to 210 miles per hour. and carved a 17-mile path of destruction throughout this area of oklahoma causing what could be more than 2 billion, with a b, dollars in damage. one of the most heart breaking scenes is this pile of wreckage, want to show you, where the plaza towers elementary school once stood. look at this. seven children died there. just taking shelter in a classroom. we learned today that president obama will be coming to this area. he'll be visiting moore, oklahoma, this sunday. we want to take you inside what is left of that elementary school. chief national correspondent john king took a tour of the school just a short time ago. and here is what he saw.