4. KERRY INTERNATIONAL DARK-SKY RESERVE, IVERAGH PENINSULA, IRELAND

Home to some 4,000 people, the Kerry International Dark-Sky Reserve occupies nearly 700 sq km along the Wild Atlantic Way tourist trail. Because it is sandwiched between the Kerry Mountains and the Atlantic Ocean, this area is relatively protected from urban light pollution. Ireland's population has always enjoyed stargazing. Some 6 millennia ago, the Iveragh Peninsula's Neolithic inhabitants erected stone monuments that show by their alignment how they attempt to track the movements of sun, moon and stars. Experts in the ancient Ogham language believe that inscriptions found in the area may describe celestial observations made during that era.