Ilmenau is a river south of Hamburg, in Lower Saxony, Germany. The Ilmenau originates in the Lüneburg Heath, south of Uelzen, at the confluence of the rivers Gerdau and Stederau in Veerßen, a district of Uelzen. From Wikipedia
Police suspect the discovered body is that of a 19-year-old who disappeared after a party, with no foul play currently suspected.