This is a resort on the slope of mount Ungaran, about 900 meters above sea level. Gedong Songo (nine buildings), a group of small 8th century Hindu Javanese temples, can be reached either by car or on horseback from the town. Built at about the same time as the temples of the Dieng complex, Gedong Songo is one of the most beautifully sited temple complexes in Central Java and the views alone are worth the trip. Gedung Songo (‘Nine Buildings’) belong to the earliest antiquities of Java, they follow up the temples on the Dieng Plateau directly, for what about time. They were also built high in the mountains in an area full with volcanic activity; and they were also from Hinduist origin. But where the temples on Dieng Plateau are somewhat squeezed into a foggy valley, Gedung Songo are spread over the higher parts of the mountains, which guarantee a splendid view. On clear days, the horizon is one long row of volcanoes, from mount Lawu in the east, towards mount Sumbing, mount Sundoro and Dieng Plateau in the west.
The temples were built between 730 and 780, the first temple excepted, which could have been built some 30 years later. Gunung Songo is not the original name and also doesn’t point at the number of structures. The number nine has a special meaning in the Javanese culture, in which there is a strong attachment to numbers. The temples are located at about the same distance from each other (100 meters, 200 meters) on a naturally formed terrace of edge of a mountain.
Quoted From http://www.indonesia-tourism.com/central-java/gedong-songo-temple.html