For centuries Mallorca suffered from geographical isolation, and frequent attacks by pirates led to the depopulation of the coast. In the Serra de Tramuntana there are numerous lookout and defence towers, articulated around a complex system of signals that served to warn of the arrival of enemy ships or seek protection from the attackers. The first towers were built in the 16th century, although the presence of guards and sentries is documented from the 14th century on. The mathematician and historian Joan Baptista Binimelis (1539-1616) was the ideologist of the coastal watchtower network. The towers were located in places with good visibility which enabled them to observe the neighbouring towers at the same time.
Today there are some exceptional observation platforms affording views of the sea and the landscape of the Serra, such as those of Cala En Basset (Andratx), La Trinitat (Valldemossa), La Pedrissa (Deià), Torre Picada (Sóller), Na Seca (Escorca) and Aubercutx (Pollença).