Human: How did the Romans build aqueducts? Assistant: 
The Romans built aqueducts to transport water from rivers and springs to cities. Aqueducts were constructed in two main ways: underground and overground. Underground aqueducts were usually made of stone and were often used to transport water from a spring or river to a city. Overground aqueducts were usually made of brick and were used to transport water from a river or lake to a city. Aqueducts were also used to transport water to public baths, fountains, and other places where people could get clean.