The lighthouse of Aghios Nikolaos is located at the edge of the port in the big natural gulf of Kea ‘s canal and is built over the ruins of Poseidon Temple. It was built in 1831 by the French Lighthouse Company, it has 8 m. height and was the first lighthouse ever functioned in Cyclades and the second one in modern Greece. Next to it you will find the little church of Aghios Nikolaos. Since 2010 it is characterized as a monument and appertains to the category of the antiquities under protection.