Groundwater lake in the Chukurovo open coal mine:
(Image Copyright by Johann Brandstätter/JB Photography)
The Chukurov mine is an open-pit Lignite mine near the town of Novi Han, some 35 kilometers southeast of the Bulgarian capital Sofia. Most if not all the produced coal is used in the thermal power plant Bobov Dol.
Although the mine is active, a lot of wrecked machinery standing around like the two excavators parked beside the groundwater pool on the lowest level of the mine.
By the way, the color of the water is natural, not thanks to Photoshop (just a little enhanced saturation).
Canon EOS 50D & Canon EF 70-200mm L USM (@200mm); f/8.0; 1/800; ISO 200