Question: What event in 1170 may have caused the creation of 5,000 km2 large shallow bay of the North Sea in the northwest of the Netherlands?
Sentence (from "Paratethys"): The Paratethys ocean, Paratethys sea or just Paratethys was a large shallow sea that stretched from the region north of the Alps over Central Europe to the Aral Sea in Central Asia.
Relevant evidence: No