The 26 km long Tazha river springs from the southern slope of Zelenikovets peak. Its spring is located 1.4 km south of Maragidik peak. From there, the river descends between the southern slopes of the Balkan Mountain, enters the Kazanlak field and then flows into Tundzha river. In its first 4 km, the river flows to the east, then turns south and continues into a narrow canyon valley with numerous waterfalls. The Kademlijsko and Babsko praskalo are two landmarks located on the left tributaries of the river. Exiting the mountain, Tuzha river cuts the rocky walls of the picturesque Tuzha Gorge – part of the “Dzhendema” Reserve. On the slopes of the gorge are situated Kupenite, Kozya Stena and Paunov Peaks – rock towers, with rooms cut into them, part of an ancient fortress.