with what they got just by being without any warning in toxic fumes for so many weeks and months when the government of the united states said there was nothing to worry about. >> you're so right. it's the almost singular tragedy while two decades ago, the death toll is not a static number. it changes. it has grown gradually over these 20 years. andrea mitchell at our post at the pentagon. we'll bring in geoff bennett, she's in shanksville, pennsylvania. it's home of the flight 93 national memorial. jeff, tell us what will happen there today. >> good morning. the ceremony here will pay tribute and honor to the selflessness of those 40 american heroes that were on