The ancient town of Ikos at Kokkinokastro in Alonissos: At Kokkinokastro beach, the remains of the ancient city walls, pot shards, and graves seem to have deepened the belief that this is the ancient city of Ikos. In fact, evidence of Neolithic settlements has been found there. The fossil remains of mainland animals like rhinoceros, pygmy-horses, and deer suggest that the Sporades islands must have been connected to the mainland of Greece once upon a time.
It is believed that the town of Ancient Ikos was situated at Kokkinokastro area, whose name means Red Castle, near the south cape of Tzorti Bay. It is there that the remains of town walls and tombs have been unearthed. Paleolithic Age tools have also been excavated.