We need water to live, so it's no coincidence that many ancient civilizations sprang up around natural water sources. But the ancient Greeks and Romans found a way to thwart, or at least divert, nature with the invention of aqueducts. Aqueducts were used to transport large amounts of water from one place to another, sometimes over as far as 60 miles (96.6 kilometers). They used the force of gravity to move water downhill via manmade conduits constructed at a steadily falling incline.
The aqueducts were mainly made of materials like concrete, cement, brick and stone. They would often originate at springs in hilly areas, but damns and reservoirs were also built to feed them from rivers or streams. When we think of aqueducts, the arcades, or aboveground stone bridges supported by arches, spring to mind. But the aqueducts were also made up of shorter walls, covered ground-level trenches, underground tunnels and pipes to facilitate the water's travel across a wide variety of landscapes.
An aqueduct's destination was a distribution tank called a castellum, which was usually at a high point in the city. It sent water to smaller castella, from which it flowed via masonry conduits or pipes to feed fountains, baths, public drinking basins and sometimes even private residences.
Rome's first aqueduct was constructed in 312 B.C.E. By the time of the construction of the Aqua Traiana by the Emperor Trajan around 109 C.E., the Roman aqueducts brought hundreds of millions of gallons of water into the city daily. These waterways allowed Roman cities to support much larger populations than they would have been able to with natural water sources alone.