Plus 359 Gallery, founded in 2017, stages eight exhibitions every year at its main gallery space in the building of a preserved water tower in Sofia, Bulgaria. It was designed in 1903 by the German engineer Franz Salbach. The construction of the tower started on September 20, 1928 and ended on November 20, 1929. It was built at the highest point of the Lozenets district in Sofia, based on a French system for construction of water towers with reinforced concrete and brick masonry. The building has four floors and one ground floor. The tower’s tank, now hosting various video and audio projects, has a volume of 100 cubic meters. In the past, apart from being a hydraulic structure, the architecture of the building permitted it to serve as a watchtower. Today, this historical landmark is a space for contemporary art.