ATL Stadium - I tried placing a sunken bowl stadium at the two quarry sites near the 102 and Kearney Lake. These are too deep and much too large. One site looks like it must be at least 100 feet deep. I was the one who previously recommended a quarry - so I am embarrassed that I made such a suggestion (blame me). I had only seen these on Google maps from a distant perspective. Once I zoomed in and checked the terrain then I realized that is was a poor suggestion on my part - these really do have a chance of becoming large swimming pools (or large lakes). So such a stadium might end up submerged in water. Let's forget this and think further south at the Bayers Lake or Halifax Commons area

. You can criticize me for this idea.
For a sunken bowl stadium, just a slight depression would be best. If a large site were found that was sunken by 20 feet then it might be cheap land since it might not be desirable for many development projects. Then the dirt could be moved around to form the lower bowl of the stadium and ramps to the concourse. Based on what I read, such a method of building a stadium is a cost effective approach.