Zumaia is a small town in the north of Spain in the Basque Country. The town has two beaches, which are of interest to geologists because they are situated among the longest set of continuous rock strata in the world. These formations are termed flysch and they date from the mid-cretaceous period to the present, a time period of over 100 million years. The K–T boundary is present at the Itzurun beach, and fossils can be found, notably of ammonites.