The solid walls of Castle Visconti San Vito have helped it withstand the test of time. Admire the architecture of this grand building from afar or see if there are any tours.
You're spoiled for sightseeing choice when in Somma Lombardo. Castle Visconti San Vito is an ideal place to start here, but there are lots of other worthwhile places to discover. Safaripark, Volandia Museum of Flight, and Lake Comabbio are not far from the fortified complex and and will cap off your day nicely.