When they were christened in 1972, the twin towers were the largest buildings ever built – and they survived 23 years without any major incidents. Discover how the World Trade Center towers were built, how they survived a terrorist attack in 1993 and why they came down eight years later. CGI graphics and eyewitness interviews unravel the split-second events of September 11th in visual detail, explaining the answers to the questions that haunt the American public. If it didn't fall from the first terrorist attack in 1993 and it didn't fall when the planes hit, then why did both buildings eventually crash to the ground? Witness interviews with the men who created these gigantic structures, including structural engineer for the WTC project Leslie Robertson and architect Minori Yama Saki, and hear their answers.