"Was tun?" (What to do?) is one of the most famous and striking murals by Klaus Klinger and Farbfieber e.V. in Düsseldorf. It was also the title of his major anniversary exhibition at the NRW-Forum, celebrating 30 years of the local street magazine fiftyfifty. It was painted in 2008 with the collaboration of Marq Eichberger, Marc Hennig, and Monica Londono as part of the Mural-Mobil project.
The facade sits directly alongside the train tracks just outside Düsseldorf Central Station. Countless commuters and travelers entering the city from the north are greeted daily by this thoughtful ape and the question "Was tun?".