On this stage we are greeted for the first time by the much longed-for Adriatic. Here, in the region around Gradisca, the River Isonzo is of special historical significance. The rough yet charming karst landscape dominates the entire course of the route until it drops steeply to the sea at the magical Duino, on the trail of the famous poet Rainer Maria Rilke.
The Isonzo region (Isontino) consists of two main areas: the plain to the west and the karst to the east. These are two very different environments, especially as far as the existence of water in the ground is concerned, on which the vegetation, fauna and human activities depend. The Isontino karst or Gorizia karst is a habitat which is difficult because of its character but at the same is very interesting in terms of its natural history. During the First World War it was severely affected and driven into poverty. The so-called Zona Sacra on Monte San Michele with its defensive trenches and bunkers is just one example of the remnants that can still be found half-concealed in the karst. But amidst the stony landscape there is also fertile soil, the so-called “terra rossa”, which in some sections offers ideal conditions for agricultural use. Subterranean water courses from the catchment area of the Isonzo also rise to the surface here, causing unusual karst lakes to be created between Doberdò and Monfalcone. Perhaps the greatest surprise is on the other side of Monfalcone: the estuary of the River Timavo. This karst river rises in Slovenia but only runs above ground for a short distance, and then returns deep underground below the karst rock for 40 kilometres before emerging to the surface again here. With the cliffs of Duino, which form the enchanting setting for the castle of the same name which is reflected in the sea, we reach the first, rightly famous corner of the province of Trieste.
From Gradisca we cross the bridge over the Isonzo towards Poggio Terza Armata. Following the markings for the trail CAI 70 we cross both the provincial road SP8 and the railway line. We go along a vehicle track which leads uphill and come into the forest. At the first junction we turn left following the markings for trail no. 76. Via a stretch which is almost entirely in the forest, we come to the asphalt road which takes us to the war museum of Monte San Michele. Above the museum we scale the summit of this mountain, which has sadly acquired fame as a theatre of war but gives us a 360-degree view of the Isontino karst. We continue along a trail running northwest through the Zona Sacra, which we leave on the first clearly visible turnoff on the right-hand side leading downhill. On a vehicle track via a section running in the opposite direction we reach the village of San Martino del Carso. We leave the village heading in a southerly direction and watch out for the markings for trail CAI 72, which takes us through the karst to the lake of Doberdò. After the village of Marcottini and after we have crossed the provincial road SP15, a long section through the woods awaits us until we come to the Colle Nero-Castellazzo area, where we finally catch sight of the lake from the steep southern slope at Casa Cadorna. Here we are above a nature reserve, and with a bit of luck and patience we might see one or other bird species in flight. From Casa Cadorna the route leads downwards beneath the rock walls, then straight on downhill to the road (CAI 72) and on to the lake. On the path around the lake there are viewing platforms close to the water. We follow trail no. 72 as far as the junction with the asphalt road which leads down from Doberdò. We keep heading eastwards on this road until after a pronounced bend we change to a vehicle track which brings us back to trail no. 72 again. We follow the trail markings eastwards along a comfortable vehicle track until we are below the Monte Arupacupa, and this leads us downhill to Iamiano. We walk through the village and then follow trail no. 3. Walking along narrow gravel roads through pine forests and shrubbery, we come into the province of Trieste without even noticing. Shortly before Medeazza we take a vehicle track which leads in a straight line downhill (CAI 16). Once we have reached the main highway SS55 we are close to San Giovanni del Timavo. Via the SS14 we come to the bank of the Timavo, where we can check the water level of this special karst river. We follow the CAI 1 towards Villaggio del Pescatore and the Cernizza forest (here we pass the archaeological site of the Antonio dinosaur) and reach Duino. Here we go past Duino Castle (the castle of the princes Torri and Tasso), come to the Rilke Trail and can thus hike along the trail of the famous poet Rainer Maria Rilke.