Cistern

Used to store water and supply fountains, water tanks were an essential component of Hellenic cities. A reliable and steady source of water, stone tanks could be filled using mechanical devices such as Archimedes’ screw or by siphons, which were used in Pergamon's citadel. Many Greek inventions and innovations stemmed the harnessing of water, including the 'clepsydra', a type of clock known as a water thief. Although water clocks had been used for centuries to mark time with a controlled flow, it was Ctesibius, an Alexandrian inventor, who is supposed to have improved the design. He is also responsible for the 'hydraulis', or water organ.