Lake Madine is a huge lake spanning 1,100 ha (2 718 acres). It was filled with water in 1976 to set up a drinking water reserve supplying the town of Metz and its surroundings. It is classified as an Important Area for the conservation of Birds with more than 200 species on the site. An observatory was built on the edge of the lake: perfectly integrated into the landscape, it offers optimal viewing conditions in all seasons.