At the northern end of Kilkis is the most important green lung of the city. The "Hill of Agios Georgios", which takes its name from the 19th-century Monastery that dominates the top, is the most popular destination for hiking, with a climb of 369 meters which is the highest point, for running or cycling.

The Hill offers the best panoramic view of the city and the plain of Kilkis. At the foot of the green area of 628 acres, the Open Theater is built, while on the hill there is a cafeteria. Underground, at the heart of the hill, the wonderful Cave of Saint George is hidden.