Maybe it’s from all the tall buildings and pizza! In the last 100 years, Chicago and some places south of Lake Michigan have sunk 4 inches. It’s not done there! The city is expected to continue sinking 4 to 8 inches every century. While 4 inches over 100 years does not seem like much, the Tribune reports that this could eventually redefine flood planes. Maybe if we all went on a diet, we could slow the process!