Wikipedia
Panchaea ( Greek: ) is an island, first mentioned by ancient Greek philosopher Euhemerus in the late 4th century BC. Euhemerus describes this place as home to a utopian society made up of a number of different ethnic tribes and his trip there in his major work Sacred History, only fragments of which survive.
Fragments preserved by followers such as the later Greek historian Diodorus Siculus and 4th century AD Christian writer Eusebius of Caesarea describe Panchaea as a rational island paradise located in the Indian Ocean. Euhemerus came there by traveling through the Red Sea and around the Arabian Peninsula; in the island's temple of Zeus Triphylius he discovered a register of the births and deaths of the gods, proving they were merely historical figures. The island is also mentioned by Lygdamus (Tib. 3.2.23), one of the Tibullan elegists, as a rich place from which he'll hope for gifts to his grave.
Several islands may be probable locations, including Socotra or Bahrain. The place may resemble the Failaka Island, although it is unlikely Panchaea was a real place, but rather a literary device invented by the author. In many parts its description is similar to Plato's Atlantis.