A visit to the Konzerthaus is a must for all classical music fans. Opened in 1913, it has outstanding acoustics and attracts some of the world's best orchestras. The Vienna Philharmonic traditionally starts the season on New Year's Day with a performance of Beethoven's Ninth Symphony. Over the following 12 months, more than 700 different concerts take place in the four concert halls; the majority are classical, but there is also a handful of jazz and world music events such as the Internationale Musikfest. A highlight of the classical music season is the annual Frühlingsfestival (spring festival).