"Dam Busters" was the code name given to the men of the Royal Air Force No. 617 Squadron whose mission it was to attack and destroy German dams. The "bouncing bombs" they deployed were especially made for this mission, Operation Chastise. The RAF succeeded in breaching the Möhne and Edersee Dams causing disastrous flooding of the Ruhr and Eder valleys, though the Sorpe Dam sustained only minor damage. The bombing of the Mohne caused a breach of about 250 feet wide by 292 feet deep (76 metres wide x 89 metres deep). Around 330 million tons of water poured into the western Ruhr region, and reached a height of 32.5 feet (10 metres), moving at a rate of 15 mph (24 km/h) deluged the valleys. Among the destruction were factories, mines, roads, railways and bridges, as well as a few homes. Also destroyed were two hydroelectric power stations. Of the 1,600 civilians drowned, 600 were Germans and 1,000 mainly Soviet forced-labourers. German production resumed but could not be restored to normal until September.
Battle of Monte Cassino: The Polish II Corps launched their second attack on Monte Cassino. Under constant artillery and mortar fire from the strongly fortified German positions and with little natural cover for protection, the fighting was fierce and often times hand-to-hand. With their line of supply threatened by the Allied advance in the Liri valley, the Germans decided to withdraw from the Cassino heights to the new defensive positions on the Hitler Line. In the early morning of May 18, the 2nd Polish Corps linked up with the British 78th Division up in the Liri valley 2 miles (3.2 km) west of Cassino town. Meanwhile, on the Cassino high ground the survivors of the second Polish offensive were so battered that "it took some time to find men with enough strength to climb the few hundred yards to the summit." A patrol of Polish 12th Podolian Cavalry Regiment finally made it to the summit and raised a Polish flag over the ruins. Total Allied Casualties was 55,000. Immediately after the cessation of fighting at Monte Cassino, the Polish Government in Exile (in London) created the Monte Cassino campaign cross to commemorate the Polish part in the capture of the strategic point. Also during this time, Feliks Konarski, a famous Polish song-writer, wrote his moving anthem "Czerwone maki na Monte Casssino", translated to English, "The Red Poppies of Monte Cassino" to honor the memory of the Polish soldiers that died fighting this Battle. At the end of World War Two, the Poles erected a Polish Cemetery at Monte Cassino on the slope of the mountain.