- Every Monday at 8pm there’s the Monday night session in domicil. On Wednesdays at 9pm there are free sessions with different topics, too. See their page for more information.
- Also every Monday at 7.30pm there’s “Klänge für die Seele” (“sounds for the soul”) in Pauluskirche, see their page for more information.
- The Iberoamerikakreis regularily presents Spanish speaking movies with German subtitles. See their page for more information
Admission to Steinwache Memorial (German history from roughly 1930-45) is free. Every 1st Wednesday of the month, the public museums are accessible for free. Also in U-Turm there are some places accessible without buying tickets, especially recommendable is the roof access.
There are many public museums in Dortmund, the pages are not translated.
- Museum für Kunst und Kulturgeschichte (museum for arts and cultural history)
- Museum Ostwall im Dortmunder U (museum “Ostwall” in U building)
Museum für Naturkunde (natural science museum)(Naturkundemuseum is closed until 2016)
- Westfälisches Schulmuseum (westphalian school museum)
- Kindermuseum Adlerturm (children’s museum “Adlerturm”)
Hoesch-Museum(museum of Hoesch steel factory, does not take part in “first wednesday” but still is interesting)
- Brauerei-Museum (brewery museum)
In addition, there are private exhibitions and museums.
- Hartware Medien Kunstverein (HMKV) in the U Building – the exhibition on the 3rd floor also is free on the 1st Wednesday of the month
- Here is a (German) article from 2013 listing museums with free admission in Ruhr area
Parks are generally free in Dortmund, with the exception of Westfalenpark (there’s a combined ticket for park and tv tower access available). See the official Dortmund page (in German) for a list. My favourite park is Rombergpark with its botanic gardens and the arboretum.
There’s also a facebook group called “Pott for free” – most of its contents are in German, though.