Since September, America has scrambled to fortify its homeland defenses. Now, with the Salt Lake City Winter Olympics just a few days away, the country faces an enormous security challenge. 48 HOURS takes an inside look at some potential threats to America, and the cutting-edge efforts to combat them. Tracking Terror: Steve Emerson and his group of specialists are obsessed with tracking Islamic terrorists and their sympathizers. Do they go too far? Whipping Up Terror: Meet an American industrial chemist who may be helping terrorists learn how to make chemical weapons. Winter Olympic Lawman: One man is in charge of making sure that the Salt Lake City Winter Olympics stay safe from terror. Can he succeed? Target: Petersburg: Marines use a U.S. city as a training ground in how to stop a deadly terror attack. Hartman At Ground Zero: Steve Hartman reports that Ground Zero has become a hot tourist attraction.