Fifty five ancient towers are situated dotted all over the island. They are all round and they have been built between 6th and the 3rd century B.C., as it is proven by the shards of ancient pots that have been found in the areas of the towers, as well as by their size and their building type. The findings also prove that the towers had ad least two levels with internal separating walls. Most of them are barely visible.
In 524 Samian fugitives come to Sifnos; they are political opponents of the shrewd tyrant of Samos, Polycrates, and ask from the residents of Sifnos to help them economically by giving them 10 talents. The residents of Sifnos refuse to give them the money and the Samians make them give them the enormous amount of 100 talents by besieging and pillaging the island.
That is when the decadence of Sifnos starts. The towers have been built after the invasion of the Samians in order to send signals to the ancient citadels.
Later on, the network has been developed and the signals exchanging system has been spread all over the island. The new communication method, according to Thucydides, must have been fire and smoke.
Later on, the towers have been used as protective buildings for the women and children and had full agricultural equipment, reservoirs, storehouses, while the stronger ones have been used to push back the pirates.
The White Tower (Aspros Pyrgos), which is situated next to the street that leads to Platis Gialos, and the Black Tower in Exambela village, are maintained in a good condition. Also visit the Tower of Katavati (400 B.C.), which is situated in the location "Kade", on the road to Vathi.
In Sifnos, within the framework of the Cultural Events, once a year – at the eve of the Holy Spirit feast – there is the revival of the towers communication system. The event takes place with the help of volunteers coming from all over the island, who "light up" as many towers as they can, bringing back to life the ancient monuments of Sifnos for one day.