The new Copenhagen Concert Hall opened in January 2009. Designed by Jean Nouvel, it has four halls with the main auditorium seating 1,800 people. It serves as the home of the Danish National Symphony Orchestra and along with the Walt Disney Concert Hall in Los Angeles is the most expensive concert hall ever built. Another important venue for classical music is the Tivoli Concert Hall located in the Tivoli Gardens. Designed by Henning Larsen, the Copenhagen Opera House ("Operaen") opened in 2005. It is among the most modern opera houses in the world. The Royal Danish Theatre also stages opera in addition to its drama productions. It is also home to the Royal Danish Ballet. Founded in 1748 along with the theatre, it is one of the oldest ballet troupes in Europe, and is noted for its Bournonville style of ballet.