Castello di San Giusto

"Once a Roman fort, this sturdy 15th-century castle was begun by Frederick of Habsburg and finished off by blow-in Venetians." Full review

"Given the excellent view, it's no surprise that 15th-century Venetians turned the castle into a shipping observation point; the structure was further enlarged by Trieste's subsequent rulers." Full review

"Within the walls are an open-air theater, the Cortile delle Milizie, where a summer film-and-concert festival is held...but the walls themselves steal the show. A walk along them affords views " Full review