The Sanctuary of Dilio Apollo is one of the most important areas of Kalymnos which flourished from the Geometric to the Roman times. There were churches, a theatre, a gymnasium, a parliament, statues, figurines and inscriptions. The temple was destroyed by the Christians during the Paleo-Christian Age and two churches were built on site, the Christ of Jerusalem Church and Agia Sophia Church (Saint Sophia). Visitors today can only see the two churches. The Temple of Dilio Apollo is located between Chorio and Panormo.
In the northeast of the coastal settlement Emporios there is a fortress from the Hellenistic Age, Kastri with strong walls, two defence towers and a gate. In Kastri operated an olive press and this is obvious from the ruins of ancient olive presses located west. Kastri was built for shelter in emergency situations. Its position offers efficient observation of the surrounding area as well as the sea.
In the Paleo-Christian Era (4th - early 7th century AD), Vathis flourished more than ever. It was the largest settlement surrounding the port of Rina in the southern part, named Hellenica. Churches, houses and arched graves have been kept in remarkable condition in some cases up to roof height. In Vathi there are ruins of thirteen Paleo-Christian Churches. These are: Agia Sophia (Saint Sophia), Anastasi (Resurrection), Agios Georgios (Saint George), Agia Irini (Saint Irene), Vasiliki Ikopedou Chalkiti, Unknown Church, Paleopanagia,
The Castle of Chora is located northeast of Chora settlement and it was built in the 11th AD century and was repaired by the Knights of St. John in the late 15th century. Till the early of 18th century the Castle of Chora was the residential centre of Kalymnos. In the Castle of Chora there are ten churches still preserved and their interior still shows wall paintings from the end of 15th - early 16th century.