The Bavaria Film Studios and a castle are in GrÃ 1\/4 nwald . GrÃ 1\/4 nwald is best known for its medieval castle of the Wittelsbach , for the Bavaria Film Studios ( one of Europe 's biggest and most famous movie production studios ) , and as a domicile for many prominent and rich people ( GrÃ 1\/4 nwald is one of the wealthiest municipalities in Germany ) .