Question: Groningen is located south of a sea located between where? 
Sentence (from "Wadden Sea"): The Wadden Sea (Dutch: "Waddenzee" , German: "Wattenmeer" , Low German: "Wattensee" or "Waddenzee ", Danish: "Vadehavet" , , North Frisian: "di Heef" ) is an intertidal zone in the southeastern part of the North Sea.
Relevant evidence: No