In July 2002, the NAO was invited to perform for Pope John Paul II and an audience of 800,000 as part of World Youth Day 2002 celebrations in Toronto. On August 23, 2007, the NAO performed Mahler's Symphony No. 8 "Symphony of a Thousand" to a sold-out audience at FirstOntario Concert Hall's Great Hall. It was only the eighth performance of the massive work in Canadian history and was the summer finale to the 20th anniversary season of the Brott Music Festival.