They were completed in 397 BC and had the following characteristics:*Length: 27 kilometers*Width at base: 3.3 m to 5.35 m*Number of known towers on circuit: 14 (including Euryalos)*Largest tower: 8.5 m x 8.5 m*Deepest ditch (at Euryalos fortress): 9 mBuilding so big a fortress would have involved installing well over 300 tons of stone every day for 5 years.