Outside the Monolithos village is the medieval castle, built on top of a 100m rock. It was built in 1480 by the Knights of Saint John to protect the island from attacks. In fact, this castle was never conquered. The Castle of Monolithos is widely ruined today but it offers great views of the sea and the two islets opposite to it. Inside the castle, there is a small working chapel dedicated to Agios Panteleimon (Saint Pantaleon).
Access to the castle is by a staircase cut into the rock. The steps, whilst not particularly steep, are quite slippery simply due to the numbers of visitors wearing them away. On the climb up to the top, you are likely to see hundreds, if not thousands, of small piles of rocks from 3–10 in number. These piles are left there by the visitors as a form of a memento.
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.