Windmills on the Greek island of Patmos. Patmos is a small Greek island in the Aegean Sea, most famous for being the location of both the vision of and the writing of the Christian Bible's Book of Revelation. One of the northernmost islands of the Dodecanese complex, Patmos' main communities are Chora (the capital city), and Skala, the only commercial port. Other settlements are Grikou and Kampos. The churches and communities on Patmos are of the Eastern Orthodox tradition.