determined by the Association of Spanish Language Academies as being the only correct use outside official Spanish documents in which the Basque spelling is mandatory. It is also the Spanish spelling used in the Spanish version of the Constitution and in the Spanish version of the Statute of Autonomy of the Basque Country. Geography and demographics At Gipuzkoa is the smallest province in Spain. The province has 88 municipalities and 709,607 inhabitants (2011), a quarter of whom live in the capital, San Sebastián. Other important towns are Irun, Errenteria, Zarautz, Arrasate, Oñati with an old university, Eibar, Tolosa which was the provincial capital for a short time, Beasain, Pasaia, the main port and Hondarribia, an old fort town across from the French Atlantic coast. Gipuzkoa is hilly and green linking mountain and sea, and heavily populated with numerous urban nuclei that dot the whole territory. The conspicuous presence of hills and rugged terrain has added to a special leaning towards hiking, nature and mountains on the part of Gipuzkoans. Some mountains have an emblematic or iconic significance in the local tradition, their summits being topped with crosses, memorials and mountaineer postboxes. In addition, pilgrimages which have gradually lost their former religious zeal and taken on a more secular slant are sometimes held to their summits. Some renowned mountains are Aiako Harria, Hernio, Txindoki, Aizkorri and Izarraitz, amongst others. The Aralar Natural Park is a conservation area on the border of Gipuzkoa and Navarre in the Aralar Range. The rivers of Gipuzkoa are distinctly different from other Bay of Biscay rivers. They arise in the hilly Basque inland landscape (Basque Mountains), flow in a south- north direction, forming close, narrow valleys before joining the ocean. The rivers extend for a short length with only a small fluctuation in the volume of water thanks to the stable rainfall all year round, and they show an abrupt drop between origin and mouth as far as the length of the river is concerned. From west to east the rivers are the Deba, Urola, Oria, Urumea, Oiartzun and Bidasoa. Except for a narrow strip extending east from the hamlet Otzaurte (Zegama) and the tunnel of San Adrian, the province drains its waters to the Atlantic basin. Population development The historical population is given in the following chart: Infrastructure The region's communication layout is in step with its geographical features, with the main lines of infrastructure