The attack that Sifnos suffered in 524 BC, by fugitives of Samos who asked for financial assistance and were denied it, led the inhabitants to construct the towers with the aim of communicating quickly with the Acropolis in case of attacks. According to Thucydides, the smoke and fire signals transferred the message of attack throughout Sifnos. Archaeological research to date has brought to light 76 ancient towers, and their findings show that they were round and had at least 2 floors. The Towers stand out both for their construction and their number, since their number is high in relation to the size of the island, a fact that can be explained by the increased possibilities of attacks on an island that was rich in gold, silver and lead deposits. In case of pirate attacks, the inhabitants took refuge in these towers, where there were tools, warehouses for food and water storage tanks. Unfortunately, today just a few are preserved in good condition. Mavros Pyrgos (Black Tower) near Exampela, the Tower of Katavati, on the road towards Vathi (in the position “Kade”), and Aspros Pyrgos (White Tower) on the road towards Platis Gialos are in the best condition. Each year, on the eve of the Holy Spirit celebration, volunteers approach the towers and the acropolis, after walking, and revive the system of communication with the fires.