The Uggleviksreservoaren (Uggleviken Reservoir) is a water storage facility located in the Lill-Jansskogen forest in Stockholm. Built in 1935, the cistern contains 18,000 cubic meters of water and has enough stored energy to prevent it from freezing even during the coldest of winters. The poured-concrete structure was designed by the Swedish modernist architect Paul Hedqvist. It is composed of 64 pillars that each stand 14 meters tall Over 6,000 cubic meters of concrete was needed for the construction, and over 700 tons of steel the reinforce the building. Located in central…