Lesbos , sometimes referred to as Mytilene after its capital, is a Greek island located in the northeastern Aegean Sea. It has an area of 630 sq mi with almost 200 miles of coastline, making it the third largest Greek island. It is separated from Turkey by the narrow Mytilini Strait. Lesbos is a separate regional unit of the North Aegean region, and the only municipality within it. Its population is approximately 86,000, a third of which lives in its capital, Mytilene, in the southeastern part of the island. The remaining population is distributed in small towns and villages. The largest are Plomari, Kalloni, the Gera Villages, Agiassos, Eresos, and Molyvos (the ancient Mythimna). Twelve historic churches on the island were listed together on the 2008 World Monuments Fund's Watch List of the 100 Most Endangered Sites in the world. Exposure to the elements, outmoded conservation methods, and increased tourism are all threats to the structures.