Gråborg is the largest ancient castle in Öland. It was built probably in the 6th century and enlarged through Middle Ages. According old tax reports dating back to the year 1450, Gråborg was owned by Vadstena abbey and functioned as a some kind of trade center. It was used for defence against Danish even in 1677. According to legend Gråborg was strongly associated with king Burislev Sverkersson who had grown up there with his half-sister Sofia of Minsk.
Gråborg Castle consisted of a circular wall, about 4-7 meter tall. There were three entrances and one of them was vaulted in the Middle Ages. Archaeological excavations have revealed lot of findings, which are stored today in Kalmar Museum.
There are medieval ruins of the chapel of St. Knut on the north side of castle.
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.