Start at the car park providing access to the Marais du Quellen, located on the right of the D788 when coming from Trébeurdun, just before the youth hostel.
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(S/E) Cross the D788 and follow it to the right. After a few metres, take a smaller road on the left and walk alongside a car park. At the crossroads, turn left and, at the fork that immediately appears, take the right-hand path. After passing the houses on the left, turn left onto a dirt track. This will take you to Toënno beach. Leave the beach quickly by following a track on the right. You will reach the small menhir of Toënno.
(1) Pass the fishmonger's buildings on your right and continue along the shore. Go around a shipyard and continue eastwards along the seafront. Near the road, cross a stream and continue north then north-east.
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(2) At the T-junction, follow theGR®34to the left. You will come out onto the D21 (on the left, access to Ile Grande).
(3) Follow the road to the right.
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(4) After about 100 metres, turn right onto a path between ferns and bushes to reach the Prajou-Menhir covered walkway. Retrace your steps.
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(4) Follow the D21 to the right. At the end, cross the D788 (take care) and first turn left then right to follow a small road towards a campsite. At the crossroads, continue straight ahead (on the left-hand lane).
(5) At the crossroads, turn left onto Chemin de la Chapelle and head towards Penvern Chapel. Retrace your steps.
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(5) Turn left (when returning from the chapel) and head south on the small road that climbs in a series of small bends. The road gives way to a path that passes at the foot of a water tower. Shortly afterwards, at a T-junction, turn right. At another crossroads, turn left.
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(6) Take a path on the left (signpost) towards the Menhir de Milin Ar Lann, which is just a hundred metres away. Retrace your steps.
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(6) Continue along the path on the left (south-west). Descend into a small valley and cross a stream. Climb back up the valley and reach the hamlet of Kerariou (ignore a path on the left). Cross a road and continue north-west downhill.
(7) Turn left onto the Marais du Quellen path. The route alternates between paths on dry land and wooden footbridges over the water. After a wide circular loop that goes around the marsh to the south, you will come out onto the D788. Follow the road to the right and return to the starting point (S/E).