On the departmental road 846, at the foot of the Barrage des Dardennes, take the small Route des Camps and park in the car park at the edge of the lake.
(S/E) Walk along the edge of the water northward, and then take the yellow-marked path which leads you to the Ragas(1), taking a few steps to the left. Retrace your steps and take the path that rises left. About 400m further on, turn left in the Ravin du Cierge that runs along a dry riverbed following yellow markers. Walk under several power lines. This path is not shown on the IGN map, so the distance and the route indicated on the site is approximate. After a few switchbacks, you get to the road called the Chemin des Tourris. Take a left/right to cross it and follow the Chemin des Turcos. Continue along the track for 50m and you'll reach a junction with a trail.
(2) Ignore the trail on the right which you'll return on and continue straight ahead for a while, going under several power lines already passed, without leaving it until you reach a tank .
(3) Take the trail to the right before the tank. This is contrary to what is shown on the map, which shows the trail after the tank. Climb this trail to the top following the blue markers, without leaving it because you could get lost in the maze of white rocks dotted with crevices, called the Glacier de Pierres.
(4) You'll arrive at the Pyramide de Cassini where there's a magnificent 360° view (ideal for a lunch break).
Don't take the path that descends immediately to the right, fully south, but take the new trail southeast, which is not plotted on the IGN map. Follow the red markers and another yellow one, do not leave this trail which descends through a wood.
(5) At an intersection, not shown on the map, take the right-most descending path with yellow markers. Follow these yellow markers. Stay on this path until you reach an old quarry that overlooks the road (Chemin des Tourris), to get back to the Chemin des Turcos.
(2) Turn left on the track and cross the road to resume the yellow markers. Descend back down to the left on the path taken on the outward leg, through the Ravin du Cierge passing by the Ragas(1) to return to the car park (S/E).
