The Jahnstadion is a stadium in Marl which was built in the mid-twenties and had an initial capacity of 36,000 spectators. After several years without usage, the stadium became the home of the local baseball team 'Sly Dogs' in August 2008.

This video shows the opening ceremony of the baseball season 2011 with cheerleader performances, batter trainings, running-ins of the 'Sly Dogs' players and five energetic characters right in the middle of it.