This trail is called the Sentier des 2000 (2000 Trail) because it is all above 2,000 m (6560 ft). It features awesome alpine views of glacier-covered peaks over 3,000 m (10,000 ft) tall and the val Cenischia (valley) at 1,000 m (0.6 mi) far below you. The Lac du Mont Cenis lies a few hundred meters/yards below. A number of forts from the late 1800's can be found along the route. The forts were actually built by Italy but the area became part of France after World War II.
From the Col du Mont Cenis (Mount Cenis Pass), the trail climbs slightly on a doubletrack to a small farm. After that, a narrow, technical singletrack begins behind the farm buildings and roughly follows the 2,150 m (7,050 ft) contour. From this singletrack section, you'll have a great view of Lac du Mont Cenis about 200 m (650 ft) below.
The singletrack merges with a doubletrack at 4.4 km (2.7 mi). Here, the Sentier des 2000 Access
shortcut heads to the right leading down to the main road. Continue to the left to stay on the Sentier des 2000. A short, steep climb takes you to the glacier-fed Rousseau du Ronce stream, which starts at the 3,612 m (11,850 ft) Pointe de Ronce above. After crossing the bridge over the stream, the trail heads towards the Fort de Ronce, which is still in pristine condition.
After the Fort de Ronce, a 4 km (2.5 mi) descent leads to the ruins of the Batterie la Court. This was also constructed by Italy in the 1870's but it was destroyed by retreating Germans in 1945 and lies in impressive ruins. Just after the Batterie, two roads lead down to a destroyed barracks. Continuing on the Sentier des 2000, you reach a cliff at about 12 km (7.5 mi) that has an awesome view down into the val Cenischia in Italy a full kilometer (0.6 mi) below you. You can see all the way to its confluence with the val di Susa almost 20 km (16 mi) away.
The doubletrack continues to wind high above the valley roughly following the Franco-Italian border eventually ending at a small farm.