Crowned by a metallic arch designed by Frank Gehry, Jay Pritzker Pavilion is an outdoor amphitheatre, the centrepiece of Millennium Park. It can accommodate up to 4 000 spectators in fixed seats and up to 7 000 on the oval lawn, which has a trellis feature ingeniously rigged with loudspeakers. The water-resistant lawn was especially designed to allow rainwater to drain away in 15 minutes. In summer, the pavilion hosts free concerts featuring the Grand Park Orchestra and Chorus.