By late March 2004, some Olympic projects were still behind schedule, and Greek authorities announced that a roof it had initially proposed as an optional, non-vital addition to the Aquatics Center would no longer be built. The main Olympic Stadium, the designated facility for the opening and closing ceremonies, was completed only two months before the games opened. This stadium was completed with a retractable glass roof designed by Spanish architect Santiago Calatrava. The same architect also designed the Velodrome and other facilities.