Fontico is a 14th-century Venetian-style granary near Koper's old civic centre. It was built to store grain that could be distributed during bad harvests or wartime, a practical role that says a lot about how exposed medieval port towns were to shortages.
The building is a short stop rather than a full visit, but its stone facade belongs to the same Venetian layer as Titov Trg and the Praetorian Palace. Look for it while walking the compact old town.