1 of 3Uggleviken
The water reservoir at Uggleviken. It has a capacity of 18,000 m³ and was built in 1935. A unique aspect of its design is that it has no thermal insulation - calculations showed that even with an outside temperature of -25°C, the water in the reservoir was such a massive store of heat that its temperature would only drop by a few tenths of a degree. This was subsequently proven during the cold winters at the start of the 1940's, where a thin crust of ice did form but was broken up as the water level changed. (Source: Wikipedia)
Albums: Stockholm Random Walk, Uggleviken