The “Schwaarzenhaff” nature reserve is part of the Natura 2000 zone “Valley of the Mamer and the Eisch”; its area of 6,797.60 ha makes it the largest protection zone of European interest in Luxembourg. The site includes two zones requiring special protection: the “Steekollen” near Steinfort and the “Jongebësch” quarries near Eischen. The nature reserve includes various types of habitats, such as semi-natural dry grasslands, an alluvial forest, wet meadows, and beech woods. It is also a habitat for very rare species such as alytes obstetricans (common midwife toad) and bats.

In the 19th century, Steinfort enjoyed an economic boom, closely linked to the construction of the smelting furnace and crushers in 1846. The Steinfort installations closed at the beginning of the 1930s. Nowadays the former ironworks houses a modern cultural centre, but the industrial heritage has not been forgotten; an exhibition documents the site’s history.