Strandzha Nature Park is the largest protected area in Bulgaria spanning a territory of 1,161 square kilometres (448 sq mi) in the Strandzha Mountain in the extreme south-eastern corner of the country on the border with Turkey. It was established on 25 January 1995 to protect ecosystems and biodiversity of European importance, as well as the traditional cultural, historical and folklore heritage of the region. The altitude varies from 710 metres (780 yd) on Gradishte Peak to 0 metres (0 yd) at the Black Sea coast with average length of 50 kilometres (31 mi) from west to east and 20 kilometres (12 mi) from north to south.