It is a special piece of natural beauty in the centre of the Fthiotidan land. A narrow passage forming towering, Vertical Mountain slopes at Oiti and Kallidromos. A gorge that leads the waters of Eastern Oiti to the Sperheios River and through it to the Maliakos Gulf, creating a wetland of huge ecological importance.
The gorge is well known since ancient times. At the exit, on the outskirts of Oiti and Kallidromos, on the south eastern side of the Sperheios valley, ancient Iraklia (Trahina) was situated. It was one of the five cities in Achilles Kingdom.
In the centre of the Gorge, towards the side of Otis, “Kouvelos”, dominates the top of its peak, where there was once an ancient settlement. It is an interesting route for visitors, which starts under Papadia Railway Bridge and ends at Asopos Bridge at the end of the Gorge.