About 250 million years ago, almost all the continental masses formed a megacontinent called Pangea. In the Geopark, the opening phase and rupture of a branch of the young Atlantic Ocean, the Bay of Biscay, is recorded in the rocks, and in this activity we will contemplate the evidences that exists in Mutriku of the split that was formed between the coast of Brittany and the north of the Iberian Plate. In this split, continental fragments disappeared under the sea.

We are going to unravel the remains of one of those Atlantises, the Landes Massif, in the form of underwater avalanches with large and small cobbles.

It is a typical geological activity: at the first glance the evidence seems not very promising, but by pulling the thread, we will reconstruct an entire landmass from a few cobbles.

The activity is designed for those who want to know the history of the opening of the Bay of Biscay. It forms a unity with the activity "Mutriku's giant ammonites".

We will walk on easy terrain (sand and pavement).

Recommended for children with an interest in natural history ages 12 and up.