Simplify the following text for a Grade 5 native English-speaking person.
Original: Important cities along the Lahn include Marburg , GieÃ en , Wetzlar , Limburg an der Lahn , Weilburg and Bad Ems .
Simplified: It flows through the towns Marburg , GieÃ en , Wetzlar , and Limburg an der Lahn .