Festungsfront Oder-Warthe-Bogen

The Festungsfront Oder-Warthe-Bogen (lit. 'Fortified Front Oder–Warta Bend'), also called the Festung im Oder-Warthe-Bogen or Ostwall (East Wall), and in Polish the Międzyrzecki Rejon Umocniony, MRU (Międzyrzecz Fortification Region), was a fortified military defence line of Nazi Germany between the Oder and Warta rivers, near Międzyrzecz. The part around Międzyrzecz (Meseritz) has been colloquially referred to as the Regenwurmlager (lit. 'Earthworm camp').

Source: Wikipedia — Festungsfront Oder-Warthe-Bogen (CC BY-SA 4.0)