A total of 77 towers are still preserved in Sifnos, which date back during the period of the island's prosperity in the 6th century BC. These fortifications and defensive structures were created to serve both as observatories and as outposts.
Their original location was near the mines and with the passage of time they spread in the rest of the island, on hillsides and at the tops of hills. All the towers that have been recorded by the Archaeological Service were round and communicated both with each other and with the ancient citadels using smoke signals or mirrors (known as fryktoria).
The most accessible towers (with respect to their location) include the Black Tower in Exambela (5th cent. BC), the Tower in Kade (4th cent. BC) and the White Tower in Pantokratoras (6th cent. BC).