Even with the decision to protect the borders, the fact that Poland was virtually encircled from three sides by the Germans caused the decision that some areas were almost impossible to defend and so had to be abandoned early on. That was the case for the northwestern Pomorze Voivodship and Poznań Voivodship. A separate force, the Land Coastal Defence, was to protect key parts of the coast as long as possible, and most of the surface Polish Navy was to be evacuated to the United Kingdom as specified in the Peking Plan (submarines were to engage the enemy in the Baltic Sea, according to the Worek Plan). The main Polish defence line was to be formed on the regions of the Augustów Primeval Forest - Biebrza River - Narew River - Vistula River (and the towns of Modlin, Toruń, Bydgoszcz) - Inowrocław Lakes - Warta River - Widawka River - town of Częstochowa - Silesian fortifications - town of Bielsko-Biała - town of Żywiec - village of Chabówka - and the town of Nowy Sącz). The second defensive line was based on the Augustów Forest - Biebrza River - Narew River - Bug River - Vistula River - and Dunajec River. Finally, the third defensive line involved retreating southeast towards the Romanian border and holding as long as possible in the region of the Romanian bridgehead.