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.