evidence: The Dollart (German name) or Dollard (Dutch name) is a bay in the Wadden Sea between the northern Netherlands and Germany, on the west side of the estuary of the Ems river. Most of it dries at low tide. Many water birds feed there. [...] The Dollart Bay was probably created in the 15th century, caused by rising water levels, sinking land surfaces, storm surges and civil strife. Though the land was protected by dikes, feuds between the main Schieringer and Vetkoper parties were detrimental for community efforts. As a result, dike maintenance was neglected and sluices were destroyed. From 1413 onward the sea overflowed the district of (Reiderland) and large parts of the Oldambt district. By 1520 the Dollart had its largest extension. Between the 16th and the 20th centuries, two third of drowned area have been reclaimed again. Nowadays the unembanked forelands have been declared world natural heritage. They are a paradise for all kinds of birds and other aquatic species. The organisation for landscape protection in Groningen Groningen, Het Groninger Landschap, offers excursions into the Dollart area about three times a year.