Geleucht, a memorial in the shape of a mining lamp on the Halde Rheinpreußen, a spoil tip in Moers, Germany. Designed by Otto Piene, the 28 m (92 ft) tall monument was constructed in 2007 and contains an observation deck at the top. The Halde Rheinpreußen is part of the Industrial Heritage Trail in the Ruhr area.Photo: Carschten