candidate: There are also three so - called ( " Municipal unions of special kind " , a fusion of a district and a district - free town : Besides the Regionalverband Saarbrücken ( " Saarbrücken regional association ) " , 1974–2007 : Stadtverband Saarbrücken , " Saarbrücken town association " ) , there is the Region Hannover since 2001 and the Städteregion Aachen ( " Aachen region of towns " ) since 2009 .