This activity focuses on the youngest geological section of the Geological Park from the Maastrichtian to the Early Eocene. During this interval a lot happens: a meteorite almost destroys life at the famous Cretaceous/Paleogene boundary (K/Pg, previously called K/T), and at the Paleocene/Eocene boundary, the oceans were acidifying and earth warmed rapidly. This last event is very visible on the cliffs of the Itzurun beach, and serves as a model for what may currently happen if we continue to increase the concentration of CO2 in the atmosphere by burning fossil fuels at the current rate.

We go through the sequence of layers from oldest to youngest. Apart from catastrophes, we will also find quiet moments in the sedimentation with fossils and very diverse trace fossils. It not only allows us to discover morphological forms, paleocurrent indicators, etc., but also the 'long-term' evolution, which culminates in the wonderful collision between the Iberian and European plates.

According to the IUGS (International Union of Geological Sciences), this section is among the hundred most important geological sites in the world, and is the most studied. This relevance obviously begs for depth. There is much to discover and to know. This activity is based on a good knowledge of most of the important scientific publications of this section.

We will walk on uneven terrain (sand, loose stones and rock). The slopes are limited, but some steps are somewhat complicated.

Recommended for children aged 12 and older with an interest in natural history.