trace. >> trace: jonathan live on our southeast lawn. thank you. >> trace: our cameras have followed the rebuilding of the world trade center for a year and we have witnessed remarkable progress. the result of a lot of hard work, time, and money. tonight a look at how police are protecting that investment and the thousands of visitors and office workers who will soon fill the area. rick leventhal spoke with the new york police commissioner and has more from our new york city studios. rick? >> security has been a major concern at the world trade center site since the start of the rebuilding process. police actually prompted the architect of one world trade center to change his original design, moving the building further away from the street and adding a 20-story concrete base to protect it from potential car bombs. the city is now putting more than 200 officers on patrol in