Answer:
aqueducts
Step-by-step explanation:
Romans build the aqueduct systems around 500 years ago which comprises of channels of water to carry fresh water to highly populated areas. They have built complex network of aqueducts through out their territories. Some of its remains are visible in France, Spain, Greece, North Africa, and Turkey. Aqueducts consisted of series of pipes, tunnels, canals, and bridges and water was allowed to flow using the gravity and natural slope.