Czerniakowskie Lake is a nature reserve close to Warsaw, in the Mokotów district.  It is a favorite place for Warsaw residents to go for cold bathing.  There are chimneys in the background.  They are the chimneys of the largest heat and power plant in Poland and the second largest plant in Europe.  With 3 heating blocks, 3 coal-fired steam boilers and a 100% biomass-fired K1 steam boiler, the plant heats 55% of Warsaw’s buildings, and provides enough electricity to power over 10 million 60-watt light bulbs.