the world trade center is an almost completed complex of skyscrapers in lower manhattan, new york city, u.s. it is built on the site of the original complex that was destroyed during the september 11 attacks of 2001. there are six skyscrapers in the complex and four of them have been built. there is also a train station and memorial for 9/11. one world trade center is part of it, which is the tallest building in north america.