The Historic Villages of Shirakawa-gō and Gokayama are one of Japan's UNESCO World Heritage Sites. The cultural property consists of three historic mountain villages over an area of 68 hectares (170 acres) in the remote Shogawa river valley, stretching across the border of Gifu and Toyama Prefectures in central Japan. Shirakawa-gō (白川郷, "White River Old-District") is located in the village of Shirakawa in Gifu Prefecture. The Gokayama (五箇山, "Five Mountains") area is divided between the former villages of Kamitaira and Taira in Nanto, Toyama Prefecture. The valley is in a mountain region with considerable snowfall, and these villages are well known for their clusters of farmhouses, constructed in the architectural style known as gasshō-zukuri (合掌造り), which are designed to easily shed snow from their steep roofs. The three villages are situated in a remote valley, surrounded by high and rugged mountains which receive particularly high snowfall in winter. Remoteness and difficulty of access severely restricted the connection of this region with the outside world until around the 1950s. This isolation led to the development of its unique culture and traditions, including the architectural tradition of the Gassho-style farmhouses which has been handed down through the generations. For some time this region was known as 'the last unexplored area of Japan'.[1]: 45  The Shō River lies in the centre of this region. It rises in the southern mountains, then flows northwards towards the Japan Sea along a deep, winding and narrow valley, surrounded by mountains rising to a height of 1,500 metres (4,921 ft). As a result of this steep terrain, the majority of villages in this area are situated in the narrow strips of land along the valley bottom.[1]: 45