Having successfully hosted ISCM's World Music Days in 2005, the Music Biennale Zagreb (MBZ) has once again been chosen to host this festival, now called the World New Music Days. This way, the 2011 MBZ (7-17 April 2011) will, in fact, consist of two festivals, the 50th anniversary edition of the Biennale as well as the World New Music Days. The Music Biennale will be celebrating its 50th birthday with several brand new works for the stage, performed all over Croatia. It will host several international orchestras, but it will also include a look back at 50 years of contemporary chamber music, performed at previous festivals. The World New Music Days have issued a call for works, written in, or after, 2005, with the theme Mirabilia Memorabilia (deadline for submissions: 1 August 2010). Members of the International Society for Contemporary Music (ISCM) as well as music publishers and individual artists are encouraged to submit their works according to the detailed instructions and criteria described in the call for works. An international jury will select the works for the festival's 2011 edition. The festival takes place on various locations in the centre of Zagreb. Additionally, five new productions for the stage will be performed in the cities of Zagreb, Rijeka, Split, Osijek and Varaždin. The programme of the 26th Music Biennale Zagreb is being prepared with the support of the Ministry of Culture of the Republic of Croatia and the City of Zagreb Department for Education, Culture and Sports. The festival also acknowledges the financial support of many other institutions and sponsors, the list of which can be found in our printed materials. The Music Biennale Zagreb was founded in 1961 by Milko Kelemen. It gathered a panoply of eminent figures on the international music circuit, and sublimated the very essence of the international contemporary music scene. The MBZ continues to make a profound impression on various fields of international creative activity, always looking for new music, new interpretations and new types of multi-disciplinary performing arts. Find out more: www.iscm.org/files/CallforScores2011.pdf