. >> reporter: we asked jan masongarb of the chicago architecture foundation for guidance. >> willis tower still is the tallest in terms of how high you can stand above the earth, but when you look at sort of what's totally built from the ground up, then one world trade center wins. >> reporter: one world trade center architect david childs says winning is not the point. he wants his building recognized as standing 1,776 feet tall because of what that number represents. >> the height is important in that it symbolizes that moment of our democracy 1776, can't be much more important than that. the thing about race for the height, that will always change. this one will always be 1,776. the governor, the port authority and america all if he strongly about that and that's -- felt strongly about that and that's why we've achieved that and it's important for it to be recognized as the height. >> this all lies in just how you define the tallest building. several years ago the board ruled that an antenna didn't count in height. now the question is whether height is defined as how tall the str