It's been an extraordinary journey. From Mont-Saint-Michel, in Normandy, through Brittany to Saint-Nazaire, in Loire-Atlantique, the GR34, a 2,134-kilometre long-distance hiking trail, criss-crosses coves, peninsulas, abers, cliffs, villages and even islands. Many volunteers have contributed to the rehabilitation of this former customs road.

In this issue, Sabine Quindou first goes to Port-La Forêt, in Finistère. It is indeed here that a school of excellence is nestled: the Pôle France "Course au lLarge". Its mission: to detect and select talented young skippers. And then it was in Saint-Malo that Thalassa witnessed the departure of a unique and promising sailboat, just out of the shipyard: "Grain d'Sail".

Head for the island of Giglio in Tuscany where, on January 13, 2012, the cruise ship Costa Concordia sank. Thirty-two people lost their lives in the disaster, which was caused by a reckless manoeuvre by its captain, who had also fled the ship. Ten years later, what remains of this shipwreck? His memory is still very vivid among the French victims.

In the Basque Country, doctors are now considering surfing as a therapeutic aid to alleviate the suffering associated with certain serious pathologies such as cystic fibrosis or multiple sclerosis. Patients find in surfing and contact with the ocean a great source of comfort, both physical and psychological.

Thalassa tells you the story of Fabrice and his dog "Newt". Both are administrative agents in the Port Cros National Park, one of the three islands off the coast of Hyères in the Mediterranean. "Newt" has been trained to spot the smells of pests that threaten endemic species. He also trains to spot whale trails to better protect them.

"Au fil de la Leyre". La Leyre is a little-known place in the Arcachon Bay: the Leyre. This coastal river rises in the Landes and transforms as it approaches the sea into a maze of more than 3000 hectares of channels, arms and streams. In this unique delta, a whole range of wildlife has found refuge. - "Yves Parlier, a man in the wind". Yves Parlier from Arcachon is one of the great figures of the Nouvelle Aquitaine region. The former ocean racing sailor, known for his sense of innovation, is currently pursuing a new objective: to reduce the pollution generated by cargo ships and container ships.

Facing the western tip of Finistère stands a famous 150-year-old lighthouse. According to legend, the howling of the sea and the wind sometimes drove the guardians who inhabited it mad. Marc has decided to save it from the slow deterioration that threatens it. He lived there for two months alone in self-sufficiency. With Thalassa, he agreed to lock himself in again in the company of a musician: the artist Molecule.