"The Sea is the Largest Museum in the World"

It is possible to find clues to the whereabouts of old ships that sank by looking through old documents and books. Descriptions of ships sinking sometimes make specific reference to the ship's name, and the place or even the rock where they met their demise.

Geophysical instruments allowing the detection of anomalies on the seabed are towed from the rear of the boat.

On this sonar image, we can make out not only the ripples of sand on the seabed, but also any anomalies. In the center of the image, the anomalies are in fact cannons lying in the sand.

An operator continually checks and analyzes the data gathered by the sonar.

Diving in is part of their job, so underwater archaeologists have no choice: They have to get wet!

The first stage of a search is to set up the grid at the site by physically dividing the site into squares, providing a spatial point of reference for the entire search

Underwater archaeologists use an underwater vacuum cleaner to remove the sand and sediment covering the site.

Each piece of information, each clue must be noted down. During a dive, a simple board, laminated graph paper, and a pencil are sufficient.

Photo and video documentation on site

This 18th century pulley has traveled through time protected by the sand covering it. Even the rope is still in place! Every precaution therefore needs to be taken to bring the object up without damaging it.

Underwater archaeologists have a remarkable opportunity: Objects made from organic materials (wood and leather, for example) are preserved in the sediment for hundreds or thousands of years, whereas in soil, these objects rot and are therefore very rare.

Extracting an object from the seabed is always a delicate task. Once on board, the item is taken care of using preventive preservation measures. 

An object's immersion in sea water often gives it an unusual appearance, as is the case with this bottle covered in a limestone concretion.

A ship's bell is an object greatly prized by archaeologists. That's because the inscriptions engraved on them mention the ship's name and its date of launch, thereby identifying the wreck and considerably speeding up the archaeological investigation.

Bronze is a sought-after metal and is often found in wrecks. Unscrupulous divers sometimes plunder sites by removing objects from them—a practice that is absolutely illegal.

The excavation of the wreck of the French Privateer ship La Dauphine uncovered an extraordinary pipe case, meticulously sculpted in the shape of a pistol. Three hundred years after the ship sank, the case still contained its owner's pipe!

As helpless as the Georgios itself when it sank in 1918, there was no escape for this pair of binoculars when the ship was lost off the coast of Ouessant following a navigation error during misty weather.

These musket bullets pull us straight back into the history of La Bellone, an English commercial ship requisitioned for the transportation of troops during the Napoleonic Wars. 

Depending on their material and alloy, coins tend to be pretty well preserved. One thing is certain: Gold is the material that best endures the passage of time.

On December 3, 1746, 22 months after setting sail from Lorient and just a few cable lengths from its home port, the Prince de Conty suddenly emerged from a cloud of fog and ploughed into the cliffs of Belle-Ile. Its cargo of porcelain from China and gold bars sank into the abyss.

The site, which is located at the foot of the cliff at Biéroc-la-Mondrée, lies at a depth of 20 meters and would have preceded the last ice age between 40,000 and 70,000 years ago. Excavations carried out during the 1970s resulted in the discovery of more than 2,500 pieces of carved flint.

This site consists of a barrier of stone, which was created during the Mesolithic era to catch fish on the foreshore. Due to a rise in the sea level, it is now permanently underwater—and therefore totally unusable.

During dives, archaeologists observed that the megalithic alignments in Quiberon Bay continue under the water, with menhirs visible in areas that are now covered by the sea.

The phenomenon of the sea's tides gives rise to a very special form of archaeological heritage: shipwrecks on the foreshore. Still imprisoned within the beach, these wrecks are revealed from time to time depending on the pattern of tides and storms.