The volcanic cliffs of Le Cap d'Agde and the cove of "La grande conque" with its black sand beach are the results of a series of submarine volcanic eruptions that occurred about 750,000 years ago, at the southern extremity of the Auvergne volcanic chain.
The sea eroded rock plunges it claws into the depths of the sea, which the sun transmutes into an infinite range of blue. The volcanic eruptions can still be seen in the varieties of rocks : solidified lava flows, yellow tuffs in regular layers, quartz, clay... The peak of the cliff (21 m) offers an open view on the "rocher des 2 Frères", the black sand beach, the Richelieu jetty and the Brescou Fort.
This coast of black rocks is a unique site in the Languedoc-Roussillon, to be discovered while strolling along the "sentier des falaises" (cliff path), but also by sea following the "submarine path" close to the shoreline, or while scuba diving.
The main interest of Le Cap d'Agde is to have a rich and varied marine wildlife in shallow water, nourished by abundant vegetal and animal plankton : white seabreems, sharpsnout seabreams, gorgonia, octopuses, sponges, brightly coloured sea anemones...