The remains of the Roman legionary fortress and civilian town of Brigetio, on the eastern edge of modern Komárom in the Szőny district. There is not a lot to see above ground — the visible remains are a few stretches of stone foundation, the outline of an amphitheatre — but the importance of the site is hard to overstate. This was one of the great Roman bases on the Danube frontier.
The finds are in the Klapka György Museum in town: mosaics, military diplomas, bronze figurines, and the gravestones of soldiers from across the empire. Bring the museum visit and the on-site walk together for the best sense of the place.