This lovely green area by the sea has several unique historical sights. The oldest structure on the island, Skansinn was a 15th-century fort built to defend the harbour (not too successfully, however – when Algerian pirates arrived in 1627 they simply landed on the other side of the island). Its walls were swallowed up by the 1973 lava, but some have been rebuilt. Above them, you can see the remains of the town’s old water tanks, which were also crushed by molten rock.