Danube
"Danube" is an Old European river name derived from a Proto-Indo-European "*dānu". Other river names from the same root include the Dunaj, Dzvina/Daugava, Don, Donets, Dnieper, Dniestr, Dysna, Tana and Tuoni. In Rigvedic Sanskrit, "dānu" means "fluid, drop", in Avestan, the same word means "river". In the Rigveda, "Dānu" once appears as the mother of Vrtra, "a dragon blocking the course of the rivers." The Finnish word for Danube is Tonava, which is most likely derived from the word for the river in Swedish and German, "Donau". Its Sámi name "Deatnu" means "Great River". It is possible that "dānu" in Scythian as in Avestan was a generic word for "river": "Dnieper" and "Dniestr", from "Danapris" and "Danastius", are presumed to continue Scythian "*dānu apara" "far river" and "*dānu nazdya-" "near river", respectively.
Lauter (Danube)
The Lauter, also: "Große Lauter", is a small river of the Swabian Alb, Baden-Württemberg, Germany. Its Karst spring is inside the walls of the former nunnery at "Offenhausen", a small settlement near Gomadingen. The river discharges into the Danube after 42 km. The river has a long geological history since late Miocene. Although the Swabian Alb is heavily karstified, this river's water runs aboveground all the way.