On the islet of s'Espalmador, on the point of sa Guardiola and 27 metres above the sea, stands the oldest of Formentera's five defence towers. It was built between 1749 and 1750, more than ten years before those on the south and west of the island. It is a truncated cone tower of two floors and a platform, with a parapet of six merlons and five cannon embrasures. It did not keep watch alone: it crossed fire with the tower of ses Portes, on Ibiza, to close es Freus — the channel between the two islands — to enemy ships. It is listed as a site of cultural interest. S'Espalmador can only be reached by sea from La Savina. Anchoring and landing are regulated within the ses Salines Natural Park: check the current rules before you go. Photo: Triedros (Wikimedia Commons, CC BY-SA 4.0).