1. When the 35W bridge collapsed, MPR had an interview with some expert, who spoke of harmonics and the way traffic needed to be tuned to the bridge itself, the truck's vibrations, etc.
2. In a friend's blog, she mentioned "Metro Island" heating. She wrote, "The sun from the previous day is absorbed into the metal, concrete, and other surfaces around the city and then released into the night air, making it an entire eleven degrees cooler twenty five miles from the city."