Kos or Cos is a Greek island in the Dodecanese, next to the Gulf of Cos. It measures 40 km by 8 km, and is only 4 km from the coast of Bodrum, Turkey. The island has both fertile plains and infertile highlands. The shores of Kos Island are washed by the waters of the Karpathian Sea. Its coastline is 112 km long and is caressed by long immaculate beaches, leading to its main industry being tourism.
The main port and population centre on the island, also called Kos, is also the tourist and cultural centre, with whitewashed buildings including many hotels, restaurants and a small number of nightclubs forming the famous Kos town "barstreet". The town has a 14th century fortress at the entrance to its harbour, erected in 1315 by The Knights of Saint John of Rhodes.