Several Ruhr-area cities joined the [[Hanseatic league]] during the [[middle ages]].<ref name=UAR>{{cite web |url=http://uaruhr.org/page/106209/ |title=Full Story |author= |date= |website= |publisher=UA Ruhr |accessdate=15 March 2015}}</ref> The Ruhr became a center for [[business]] and [[industry]]. Beginning in the mid [[14th century]] [[coal]] was mined along the Ruhr.<ref name=UAR/> It became a center for coal and [[Steel mill|steel production]] in Germany for over 200 years.<ref name=UAR/> In the mid [[20th century]] coal and steel industries came to an end. The buildings were then used for [[Cultural center|cultural events]] and [[entertainment]] purposes.<ref name=UAR/> | Several Ruhr-area cities joined the [[Hanseatic league]] during the [[middle ages]].<ref name=UAR>{{cite web |url=http://uaruhr.org/page/106209/ |title=Full Story |author= |date= |website= |publisher=UA Ruhr |accessdate=15 March 2015}}</ref> The Ruhr became a center for [[business]] and [[industry]]. Beginning in the mid [[14th century]] [[coal]] was mined along the Ruhr.<ref name=UAR/> It became a center for coal and [[Steel mill|steel production]] in Germany for over 200 years.<ref name=UAR/> In the mid [[20th century]] coal and steel industries came to an end. The buildings were then used for [[Cultural center|cultural events]] and [[entertainment]] purposes.<ref name=UAR/> |