world, and many people participating to have fun as their families and friends watch on. reporter: neil, the marathon will begin here on sunday with a moment of silence, and the runners are being encouraged to wear black ribbons in memory of boston. neil? neil: thank you, amy. now to jeff on a very tight security situation in chicago. jeff, what s the latest there? i stand in front of perhaps one of the most high profile targets in the u.s. the tallest completed building in the u.s. we have a camera to show you the sears tower. now the willis tower, and one target that was completely shut down after 9/11. good news is that has not happened here. we also have live picture on the edge of the district? chicago, the statue on the chicago board of trade building. also good news to report there that not a lot of heavy security