Aventicum, Roman city - Avenches, medieval-modern city

Avenches, the ancient Aventicum, was the largest city on present-day Swiss territory between the 1st and 3rd centuries AD, serving as the political, religious and economic capital of the Civitas Helvetiorum. At its peak the city held over 20,000 inhabitants and featured an amphitheatre, temples, baths and a circuit of walls stretching several kilometres — substantial stretches of which still define the modern town's outskirts. A medieval tower built directly over the main entrance of the Roman amphitheatre now houses the Musée Romain, displaying finds from the site's extensive excavations. The layering of Roman ruins beneath a medieval fortified town and a quietly functioning modern village makes Avenches one of Switzerland's most concentrated archaeological landscapes, listed as a Class A cultural heritage site of national importance.