Frictories. From the Greek word Φρυκτωρίες (Φρύγω=burn + ώρα= care).
Frictories were a communication system that was used in ancient times. From structures made of stone, located by the coast and on the mountains, locals used to "send" messages with the help of flambeau (φρυκτών). Researchers claim that many of those Frictories structures, were found at different locations such as Evia's coastline, Aegean islands, Crete and even on the top of some mountains in Evia.