The first big wave of Dutch immigrants to leave the Low Countries were from present day Northern Belgium as they wanted to escape the heavily urbanised cities in Western Flanders. They arrived in Brandenburg in 1157. Due to this, the area is known as ""Fläming"" ("Fleming") in reference to the Duchy that these immigrants came from. Because of a number of devastating floods in the provinces of Zeeland and Holland in the 12th century, large numbers of farmers migrated to The Wash in England, the delta of the Gironde in France, around Bremen, Hamburg and western North Rhine-Westphalia. Until the late 16th century, many Dutchmen and women (invited by the German margrave) moved to the delta of the Elbe, around Berlin, where they dried swamps, canalized rivers and build numerous dikes. Today, the Berlin dialect still bears some Dutch features.