The Dollart, or Dollard in dutch, is a bay on the Dutch-German border. In the late Middle Ages, this bay was created by floods and storm surges, drowning several villages. Now, the Dollart is an important breeding and feeding area for birds. The Dollart is a dynamic coastal nature reserve with intertidal mudflats and saltmarshes. Here salt water from the North Sea mixes with fresh water from the German river Ems and the Dutch river Westerwoldse Aa. Both the german and dutch parts of the Dollart are part of the Wadden Sea, inscribed on the Unesco World heritage list.