The body of Roman Civil Law, which came to be known as the Code of Justinian, served as the basis for all serious attempts at systematic European law as late as the high middle ages. It also set the base for the Church's Canon Law. There are elements of the Justinian Code in American civil law today.
All right, but apart from the sanitation, the medicine, education, wine, public order, irrigation, roads, a fresh water system, and public health, what have the Romans ever done for us?