- Termessos
Very old. According to Wikipedia: What is known of Termessos' history commences principally at the time that Alexander the Great surrounded the city in 333 BC. - Villa Romana delle Grotte, Portoferraio
A wonderful Roman villa from I century BC. If I'm not mistaken, this is the spa that included calidarium and frigidarium. - Church of St. Michael (Sv. Mihovil)
The "new" church was built from the remains of the old one.