While doing some random Google Maps browsing today, I noticed something odd in Grant Park: swarms of people, like a giant ant farm in the middle of the city. Evidently the satellite photos haven't been updated since last summer's Lollapalooza:
If you've ever wondered what a giant music festival looks like from above, here's your chance. Who knows how often this gets updated.
UPDATE: as noted in the comments, these images are actually from 2007. I guess Google updates their satellite photos even less often than I thought.