After the Red Army reached the coast of the Vistula Lagoon near Elbing on January 23, 1945, cutting off the overland route between East Prussia and the western territories,[42] the only way to leave was to cross the frozen Vistula Lagoon and to try to reach the harbours of Danzig (Gdańsk) or Gdingen(Gdynia), to be evacuated by ships taking part in Operation Hannibal. This phase of the evacuation followed two major routes: westwards, towards Danzig and Pomerania, and northwards, towards Königsberg and Pillau port.[43] About 450,000 Germans fled East Prussia over the frozen Vistula Lagoon and were then evacuated by ship from Baltic port cities.