The Temple of Neptune was erected on the Poreč forum in the 1st century. It is thought to be the biggest in Istria, although only a portion of its walls and the foundations have been preserved.
During the Antiquity, Poreč as well as all Roman towns, had a forum, the main town square known today as Marafor, and a Capitoline temple facing it. It was believed that the temple was dedicated to God Mars in light of interpreting the Marafor as the Martis forum i.e. the forum of Mars. To the north-west, also in the near vicinity of the former forum, are the remains of the Large Temple dedicated to Neptune, the god of the sea. There are some who interpret the remains as a holy ground surrounding the Capitoline from three sides. The temple, dated to the 1st century, is the biggest in Istria in spite of only a portion of its wall and foundations being preserved.
References:The Temple of Edfu is one of the best preserved ancient shrines in Egypt. It was built in the Ptolemaic Kingdom between 237 and 57 BC.
Edfu was one of several temples built during the Ptolemaic Kingdom, including the Dendera Temple complex, Esna, the Temple of Kom Ombo, and Philae. Its size reflects the relative prosperity of the time. The present temple initially consisted of a pillared hall, two transverse halls, and a barque sanctuary surrounded by chapels. The building was started during the reign of Ptolemy III Euergetes and completed in 57 BC under Ptolemy XII Auletes. It was built on the site of an earlier, smaller temple also dedicated to Horus, although the previous structure was oriented east–west rather than north–south as in the present site.