Visitors climb through the art installation 'In Orbit' by Tomas Saraceno of Argentina at the Kunstsammlung K21 museum in Duesseldorf, Germany, on June 30. The steel wire construction spans the museum's vast glass cupola on three different levels more than 25 metres above the ground. Visitors have access to the artwork and can move freely between the spheres on all three levels. The installation will remain in place until autumn 2014. Reuters/Ina Fassbender