The siren of Chalkis is situated in Balalaion street, a small road in the center of the city. The siren is on a square Enetian tower that was known with the name old clock. In 1940 for the needs of the defense of Chalkis that tower was formed so that the siren of the aerial alarm is situated on it.
The tower is of Mesaiwnian time and it has endured multiple interferences in the passing of the centuries. Its interior has plastered while repairs have been made to the stairs that lead to the highest point of the tower. Unfortunately on the outside the neighboring house has plastered a part of it spoiling in this way a historic relic of the city. The siren is in operation until today and for this reason the entrance there is not allowed.