The birch-covered slag heap between Zollverein Shaft XII and the Zollverein Coking Plant is an almost fairytale-like place. Five stone sculptures by sculptor Ulrich Rückriem encounter unique industrial architecture, a network of paths and the past of the coal and steel industry. The sculpture “Bleu De Vire I” made of French granite was created in the 1980s and is located almost at the top of the slag heap. The sculpture is reminiscent of a temple. Rückriem himself describes the sculpture, consisting of four cut-up ashlars with a roof on top, as a temple shape. Originally created not for Zollverein but for the Städel Museum in Frankfurt, the stone object and its counterpart “Bleu De Vire II” were only set up here as a pair of sculptures in the 1990s. The axial symmetry of the sculpture references the architecture of the coal mine on the one hand, but on the other hand it creates a counterpoint to the natural surface of the stone. Rückriem deliberately chose the slag heap for his sculptures: with the direct proximity to nature, he wants to draw attention to the renaturation taking place here, the reconquest by nature.