Technology
The ancient Romans also had a complex system of aqueducts, which were used to transport water across long distances. The first Roman aqueduct was built in 312 BCE. The eleventh and final ancient Roman aqueduct was built in 226 CE. Put together, the Roman aqueducts extended over 450 kilometers, but less than seventy kilometers of this was above ground and supported by arches.
Ancient Rome
The Romans constructed numerous aqueducts to supply water to cities and industrial sites and to aid in their agriculture. By the third century, the city of Rome was supplied by 11 aqueducts with a combined length of . Most aqueducts were constructed below the surface, with only small portions above ground supported by arches. Sometimes, where valleys deeper than had to be crossed, inverted siphons were used to convey water across a valley.