An early “early warning system” of impending island attack. There are 55 ancient towers on Sifnos spread over the length and breadth of island. The earliest have been dated as being built as far back as the 6th century BC whilst some are not as old, only dating back to the 3rd century BC. Most of them are hardly recognisable as towers today as the elements have taken their toll over the centuries. Aspros Pirgos or the White Tower is one of the best examples to visit. it can be found just outside the village of Platis Yialos.
The original purpose of these ancient towers is a little uncertain however the most educated opinions tend to think that they were an early warning system. According to Thoukidides, fires would be lit in the towers and the smoke would be a warning to all the people of Sifnos to let them know of an impending attack from raiding pirates.
As the network of ancient towers developed across Sifnos, they were also being equipped with water cisterns and storage spaces. It is thought that these later towers also served as protective buildings for women, children and the elderly while the men would be away trying to fight off the raiders.
There is one other line of thought, similar ancient towers have been found on other Cycladic islands, particularly those with a rich mining history like Sifnos – for example Kythnos and Serifos. It therefore leads some academics to believe that some of these towers were probably connected with the protection of mining and metallurgical activities.