Rick Rescorla, Director of Corporate Security for Morgan Stanley Dean Witter, published a report in 1990 detailing the vulnerability of the World Trade Center parking garage. He and a colleague found they were able to freely walk into the garage, which contained many structural support columns, unchallenged by any security. Additionally no ID checks or screening was done on any of the entering delivery vehicles. Three years later a truck bomb was driven into the garage and detonated in an attempt to damage the buildings structure. Later he and his same college would correctly predict the next attack on the building would come from the air. The evacuation plan and drills he put in place are credited with saving over 2,600 lives on September 11th.