Around 900 watchtowers (Latin: burgi) were built along the entire Limes to monitor the border. The towers were initially connected to each other by post paths and later by a road, the so-called Limesbegleitweg. The distance between them varied and was between 100 and 500 meters, depending on the topographical conditions. Most of the time, the towers were built on hills or elevations to provide a good view of the Limes and the land beyond. Contact with each other and with the surrounding forts also had to be guaranteed. Communication between the towers and with the forts took place through light or smoke signals. If the guards discovered something suspicious or enemies, the units in the nearest fort were immediately notified. These troops then moved out to confront the enemy.
Some special towers, such as the hexagonal tower at Gleichen, also served as survey points. With their help, for example, the straight line between Walldürn and the Haghof near Welzheim was built. Since these were particularly high or were built on prominent elevations, you had direct visual contact with the next survey point. The height of the towers was usually around 10 meters and the thickness of the walls was an average of 50 centimeters. They could only be entered via a ladder, as the entrance was usually on the first floor for security reasons. The ground floor was used as a storage room, the first floor as a living and sleeping area, and the second floor as a guard room. Many towers have a surrounding ditch, which is believed to have been used for drainage. Usually 3 - 4 soldiers were stationed here sooner or later. Where the distance to the next fort was too far or where there was a Limes passage, a small fort was often built instead of a tower (see Roetelsee small fort).