 To celebrate the millennium on December 31, 1999, the National Christmas Tree's lights turned white at midnight.The following year, Polk Aristo-Craft expanded the model train display and a new wrought iron fence was erected around the tree (replacing an older chain-link fence).In the wake of the September 11 attacks, the United States Secret Service announced on November 16 that only those individuals with tickets would be permitted onto The Elllipse for the December 6 tree lighting.