Alsum was once a small fishing village on the Emscher, which still flowed into the Rhine. The village was almost completely destroyed in the Second World War. In the post-war years the area significantly subsided as a result of the mining activities beneath it, causing further damage. The last resident left Alsum in 1965. For many years the area was used as a rubbish dump. By 1980 a heap had formed, which was subsequently covered with greenery. Today it is a popular destination among explorers and industrial photographers.