Having last traveled to low Earth orbit in March 2011, NASA's Space Shuttle Discovery took to the skies one last time yesterday, piggybacking on a modified Boeing 747. The shuttle left Florida and landed just outside of Washington, D.C., where it will join the collection at the Smithsonian Institution's National Air and Space Museum. Discovery, the fleet leader of NASA's orbiters, flew 39 successful missions over 27 years, accumulating 365 total days in space. Tomorrow, a welcome ceremony is planned at the Smithsonian's Steven F. Udvar-Hazy Center in Chantilly, Virginia. Gathered here are images from Discovery's last flight.