It was extensively renovated in time for the 2004 Summer Olympics and the 2004 Summer Paralympics, including a roof designed by Santiago Calatrava, and innovatively positioned with Enerpac hydraulics. The roof was added atop the sidelines and completed just in time for the opening of the Games. The stadium was then officially re-opened on 30 July 2004. It hosted the athletics events and the football finals at the Olympics and the athletics at the Paralympics. It also hosted the opening ceremony on 13 August 2004, and the closing ceremony on 29 August 2004 along the paralympics ceremonies on 17 and 28 September. In 2007, OAKA Stadium hosted the 2007 UEFA Champions League Final between AC Milan and Liverpool (2-1). The stadium's attendance was reduced to 72,000 for the Olympics, the initial capacity was some 75,000, though only 69,618 seats were made publicly available for the track and field events and slightly more for the football final. The turf system consists of natural grass in modular containers which incorporate irrigation and drainage systems.