Simplify the following text for a Grade 7 native English-speaking person.
Original: Pirna is located near the Sandstone Mountains in the Elbe valley , where the nearby rivers Wesenitz , in the north , and Gottleuba to the south , flow into the Elbe .
Simplified: Pirna is located at the beginn of the Elbtalkessel , where the Wesenitz and the Gottleuba flow in the Elbe .