The course of the fighting, 16-20 April 1945

The crossing of the Oder by the 1st Polish Army took place on 16-20 April 1945, as part of the Berlin Offensive of the 1st Belorussian Front. According to the Wikipedia entry, based on the Small Military Encyclopedia, the army advanced from the Baltic to the Oder in the Siekierki - Gozdowice - Moryń area between 8 and 13 April, and during the night of 13-14 April it relieved units of the Soviet 47th Army along the stretch from Cedynia to Gozdowice. The army's task was to cover the front's operations in the encirclement of Berlin.

The attack began on 16 April at 5.45 am, after a half-hour artillery preparation. According to the same source, the river was in many places more than 4 metres deep and 250-300 metres wide, and the valley between the Oder and the Old Oder was flooded to a width of 1 to 2.5 kilometres. After the first day of fighting the army held a bridgehead 9 kilometres wide, and on 18 April it broke through the main German line of defence and took the eastern bank of the Old Oder. It then moved on to pursuit operations in the direction of Oranienburg.

Earlier, at the end of February 1945, the 6th Independent Pontoon-Bridge Battalion reached the Oder at Czelin and, according to Wikipedia, set up a Polish border post there.

Gozdowice: the pontoon bridge and the sappers' museum

According to Wikipedia, between 16 and 20 April the sappers of the 1st Army built a pontoon bridge at Gozdowice, 275 metres long with a load capacity of 16 tonnes. The Sapper Monument was unveiled on 16 April 1952, and it was given its present form, designed by Czesław Piotrowski, in 1972. The Museum of the Engineer Troops of the 1st Polish Army was established on 16 April 1965 in the building that housed the headquarters of the army's chief of engineer troops in 1945. According to the entry on Gozdowice, the collections include engineer troops' memorabilia, maps of the front, models, boats, pontoons and a GAZ-46 amphibious vehicle. The road from the museum to the Oder is called the Road of Death, and beside it stands a monument from 1983 dedicated to the soldiers who organised the crossing. A viewpoint has been set up on the site of the former observation post.

The cemetery in Siekierki and the museum in Stare Łysogórki

Two kilometres south of Siekierki lies a war cemetery. According to the guidebook by Piotr Skurzyński, cited in Wikipedia, the remains of 1,975 soldiers rest there, and an obelisk from 1961 stands above the cemetery. The Wikipedia entry on Stare Łysogórki gives a different figure, 1,894 soldiers, but it refers to the soldiers of the 1st Army killed in the crossing of the Oder in the area of Czelin, Gozdowice and Siekierki, not to the number buried. The two figures therefore describe different things, and neither may be transferred to the other place. The Association of Landscape Parks of the West Pomeranian Voivodeship speaks of a National Memorial Area with a war cemetery in Stare Łysogórki and a museum of 1st Army memorabilia.

The Museum of Memorabilia of the 1st Polish Army has operated since 1965 next to the cemetery. In 1945 the building served as an exhumation headquarters, and its interior has been recreated in the cellar. In front of the museum stands an IS-2 tank from the 4th Pomeranian Heavy Tank Regiment. Opening hours and visiting rules are given by the museum.

Commemoration

Wikipedia notes that the battles for the Oder were commemorated after 1990 on the Tomb of the Unknown Soldier in Warsaw with the inscription "ODRA 16-20 IV 1945". The word "ODRA" also appears on the flame of the Tomb of the Unknown Soldier in Kraków.