The Silesian Autonomy March is a demonstration held annually since 2007 around 15 July, the date of introduction of the Organic Law for the Silesian Province in 1920. The participants march through the streets of Katowice, finally gathering on the square in front of Silesian Provincial Authority (once the seat of the Silesian Parliament). The March manifests popular support for the reinstatement of autonomy in Silesia in a modern shape modelled on European examples in Spain or Germany. The parade is decorated with flags, banners and placards, predominantly in yellow and blue – the colours of Upper Silesia. The chief organiser is the Silesian Autonomy Movement RAŚ.