A group of U.S. soldiers rode their bikes into Philadelphia on Thursday as part of a 1,000-mile journey up the East Coast organized by the Wounded Warrior Project. The ride, which is in commemoration of America's 250th anniversary, began in Jacksonville, Florida, on May 14. The journey is being completed in four groups. The riders are expected to finish Friday, May 29, at Ground Zero in New York City, where the World Trade Center towers were attacked on Sept. 11, 2001.