The rise of the skyscraper coincided with the rise of America as a global superpower, and experts reveal how expert engineering and cutting-edge technology helped power humankind's race to conquer the sky.

The World Trade Center and Sears Tower were record-setting skyscrapers made possible by cutting-edge engineering innovations, but just as these American icons set new standards in construction, dark and insidious forces were poised to undo it all.