About three million people in New York City prepared to celebrate America's birthday Wednesday by watching the nation's largest fireworks display, while hundreds of new citizens were sworn in at ceremonies around the country. The festivities took place under heightened security after the attempted car bombings and airport attack in Britain over the weekend. In Washington, visitors were required to pass through 19 security checkpoints to reach the grassy central Mall. "We're expecting a record crowd to come out this year and enjoy the fireworks," said US Park Police spokesman Sgt. Robert Lachance. Past crowds there have reached 500,000 or more.