An amazing satellite image of yesterday's crowd. Marc explains:
Geoeye, a commercial satellite company, took this image of Washington, D.C. during the inauguration. Notice the dark clumps on the mall; those are people, massed around the big Jumbotrons. The resolution has been resampled to a half-meter, which means that, if you had a big enough picture, you could identify objects that were a half meter across.