A full day of free activities and musical performances will celebrate the grand opening of Westfield World Trade Center, the expansive retail mall centered around the new World Trade Center Transportation Hub. The official opening ceremony will take place at noon, and then more than 100 shops will be ready for business, with many of the new stores offering free samples and special gifts with purchase. For a complete list of participating retailers, visit westfield.com. Also, there will be free hourly concerts all afternoon that will fill the Oculus with music; scheduled performers include the Broadway cast of School of Rock, Dr. Draw, the Harlem Gospel Choir, The Voice's Jordan Smith and a suprise A-list Grammy Award winner who will take the stage at 6pm.