People stand atop a platform at the Washington National Cathedral as they wait for signs in the sky for the arrival of the NASA Space Shuttle Discovery, being carried piggyback on a modified Boeing 747, in the skies above Washington, D.C., Tuesday, April 17, 2012, as it makes it's way to the Steven F. Udvar-Hazy Center in Chantilly, Va. (Rod Lamkey Jr/The Washington Times)