Aquincum - Budapest

The part of the city now know as Obuda is the site of the principal town of the Roman province of Pannonia.
The frontier of the Empire ran along the line of the Danube, and Budapest?s 2,000-year old forerunner was called Aquincum.
It was an important military centre, but a civilian town of merchants and artisans also grew up around it. Remains of the military amphitheatre can seen at Obuda and, a mile further on, ruins of the streets of the civilian town and some of its houses.

Source: Budapest and Surrounding Area - publication of the Hungarian National Tourism Office