There are Roman ruins galore in Croatia–from the Roman Arena in Pula all the way up to the remains of a Roman bath spa in Varazdinske Toplice. A town that gets much less attention for its Roman archaeological site is Sisak, located in central Croatia at the convergence of the Kupa, Sava and Obra rivers.
One of Siska’s primary sights to see is a famous military fort-turned-restaurant that, in 1593, managed to hold back a Turkish invasion. Another site we suggest adding to your list are the wall remains of horreuma or Roman barns. They were constructed back in the early 4th century and today are open to visitors in the archaeological park Siscia right next to the town’s iconic Cathedral of the Holy Cross, pictured above.