NEW : Young athletes light the Olympic cauldron after the queen opens the games . Performances pay tribute to British history , literature and music . Athletes are selected by a panel of judges who include actors from around Britain. Organizers had sought beforehand to keep the event 's details secret .
NEW : Young athletes light the Olympic cauldron after the queen opens the games . Performances pay tribute to British history , literature and music . The Greek delegation leads the parade of athletes into the stadium . Organizers had sought beforehand to keep the event 's details secret .