greenwald says there's a message for visitors that towers over anything. that there once was a time when americans stood united. >> this attitude that we can help one another, that we can be of service to our community and our nation, that's a lesson i want people to come away from this museum thinking about, particularly at a moment when we are so polarized and so fragmented as a society. we know how to do that. the question we want people to ask themselves is, does it take an event like 9/11 to remind us how to be the human beings we have the capability of being? this past year we saw a little bit of the same thing in response to covid. those people standing on their balconies, clapping and cheering at 7:00 every night in new york for the front line responders. that was 9/12. that was that moment. and when you come --