2002-2016 AD., Germany, Federal Republic, elongated coin souvenir, Möhnesee (Möhne Reservoir) commemorative, cf. KM Germany 209.

Germany, Federal Republic, Elongated coin souvenir issue for tourists, Möhnesee (Möhne Reservoir) commemorative, produced ca. 2002-2016 AD.,
Elongated coin - souvenir issue (ø 22-34 mm / 3,92 g), from a German 5 Euro cent issue dated 2002 of the Hamburg mint, copper plated steel (magnetic), 3,92 g. original coin weight, 21,3 g. original diameter, original coin mintage 504.000.000 , bent,
Obv.: MÖHNESEE , depiction of the Möhne Reservoir wall with two turrets, weak residues of the former coin´s reverse still visible: mint mark J , date 2002 and oak leaves.
Rev.: weak residues of the former coin´s obverse still visible: 5 EURO / CENT, globe and lines.
for the original coin: KM Germany no. 209 ; Jaeger 484 ; Schön 208 .

The Möhne Reservoir—or Moehne Reservoir—is an artificial lake in North Rhine-Westphalia, some 45 km east of Dortmund, Germany. The lake is formed by the damming of two rivers, Möhne and Heve, and with its four basins stores as much as 135 million cubic metres of water.
Calculations of the future demand for water for the people and industry in the growing Ruhr-area in 1904 had revealed that the existing dams in the river system of the Ruhr with a storage volume of 32.4 million m³ would require the triple amount. Thus was generated by the general assembly of the Ruhrtalsperreverein on November 28, 1904 an amendment to the construction of their own dams. The Möhnetalsperre was then in 1908 to 1913 built at a cost of 23.5 million marks. In the opening the dam was the largest dam in Europe. 140 homesteads with 700 people had to move. It was built to help control floods, regulate water levels on the Ruhr river downstream, and generate hydropower. Today, the lake is also a tourist attraction.
The dam (51.489307°N 8.058772°E) was breached by RAF Lancaster Bombers (“The Dambusters”) during Operation Chastise on the night of 16–17 May 1943, together with the Edersee dam in northern Hesse. Bouncing bombs had been constructed which were able to skip over the protective nets that hung in the water. A huge hole of 77 m by 22 m was blown into the dam. The resulting huge floodwave killed at least 1,579 people, 1,026 of them foreign forced labourers held in camps downriver. The small city of Neheim-Hüsten was particularly hard-hit with over 800 victims, among them at least 526 victims in a camp for Russian women held for forced labour.
Though the Organisation Todt quickly repaired the dams with forced labourers commandeered from the construction of the Atlantic Wall, the impact of the raid on German industry in the Ruhr valley and indeed on the civil population was significant. In the Möhne and Ruhr valleys, 11 factories were destroyed, 114 seriously damaged, 25 road and rail bridges were destroyed and throughout the region power, water and gas supplies were seriously disrupted. Industry production was back at normal level by September, however.

More on https://en.wikipedia.org/wiki/Möhne_Reservoir