An aqueduct is a water pipe
An aqueduct is a bridge for a watercourse (river or canal) in which other traffic flows (car traffic) under the water are routed through. The general thought is that an aqueduct is an invention of the Romans, but that is not entirely correct because they have been used much earlier. The Romans made them popular because they solved the problems of water supply with the aqueducts. The water transport was often underground, but this was not possible everywhere. An aqueduct is a huge building of concrete and stone. A well preserved aqueduct is Pont du Gard in France (it has a length of 275 meters and is 50 meters high). In Rome aqueducts are still used for the transport of water, in the Netherlands they were also sometimes used.