Ancient Roman aqueducts are an engineering feat thought impossible at the time. Ancient Roman aqueducts were an engineering marvel unlike any other at this time due to their history, construction, and impact on society. An aqueduct is any artificial bridge or viaduct that carries water. Aqueduct derives from the Latin words “aqua” (water) and “ducere” (lead) (“Ancient Roman Aqueducts”). Although aqueducts are a symbol of the engineering progress of the Roman Empire, aqueducts are not a Roman invention. In 691 BC the Persians invented the qanāt, or a canal that transports water from the depths of the subsoil to the surface. In 530 BC the Greeks built a primitive aqueduct. While the Romans didn't invent aqueducts, they perfected them. At the height of the empire, eleven aqueducts supplied Rome: Aqua Appia, Aqua Anio Vestus, Aqua Marcia, Aqua Tepula, Aqua Julia, Aqua Virgo, Aqua Alestinia, Aqua Claudia, Aqua Anio Novus, Aqua Traiana, and Aqua Alexandrina. These eleven aqueducts were built over 538 years, from 312 BC to 226 AD (Schram, Wilke D.). The eleven aqueducts transported a total of 200 million liters of water per day to Rome (Wulf, Caroline). The aqueducts provided each citizen of Rome with more than 265 liters of water per day. This is much more than most modern water systems can offer today (Layton, Julia). In the early days of aqueducts, the water they brought was used in government buildings, mining, agriculture, and spas (“Ancient Roman Aqueducts”). As Rome's population grew, major aqueducts served government buildings, baths, public fountains, homes, and latrines throughout the city (Cote, Michael). The aqueducts of ancient Rome worked entirely thanks to the force of gravity. Every mile, the aqueduct dropped a few feet to ensure a constant flow of water (Layton, Julia).