Only a few remains are left of the Rocca of Arona. It was the twin of the Rocca Borromea of Angera, which still stands whole on the opposite shore: together they controlled the lower end of Lake Maggiore, one from each bank.
What to see
The fortress was founded shortly before the year 1000 under the Lombards and for centuries served only to defend. Destroyed by the Della Torre, it returned to the Visconti in 1227; in 1439 Filippo Maria Visconti granted it in fief to Vitaliano I Borromeo, and the Borromeo held it for four centuries. Here, in 1538, Carlo Borromeo was born.
Visiting
What you visit today is the hill and what is left on it, with a view over the lake that explains by itself why a fortress stood exactly there. The end came in 1800, when the Napoleonic army was ordered to dismantle the fortifications held by the Austrians.
Our editors' tip
Look across towards Angera, on the Lombard shore: the twin fortress is still intact, and it is the quickest way to picture what this one was before 1800.