World Heritage. The Sierra de Tramuntana mountain range is the backbone of the north-west of Mallorca, and has been declared a World Heritage site by UNESCO due to its cultural and scenic value. Seen from the sea, some stretches of the mountain range still have an unspoilt appearance, similar to the one the ancient navigators who crossed this part of the Mediterranean must have contemplated, wild and vertiginous, softened by coves with crystalline waters. Travelling along it on board a boat enables you to reach places that are not accessible over land.