The emirates on the eastern coast of the Arabian peninsula are mountainous, and make a cooler escape for emiratis suffering from the heat of Dubai and Abu Dhabi. In nearby Fujairah, the oldest mosque in the Emirates is a 15th century mud and brick structure, glowing white, with four domes overshadowed by a ruined fortress nearby. The rugged peaks of the Hajjar range are corrugated by deep wadis, some of which hide fresh green oases tucked between their steep walls.