Hidden between Zumaia and Mutriku, one can find a landscape of steep cliffs and layers of rock emerging from the Earth. The Flysch is one of the most important geological phenomenons in Spain due to its unique scenery provoked by an occurrence known as a wave-cut platform or coastal bench.
As a result, layers and layers of rock due to erosion are revealed, even more so at low-tide along the beach of Itzurun. This spectacle shows more than 60 million years of geologic history, where each layer represents a different geologic era.
The Flysch has turned into the home of many different types of algae and seaweed, as well as molluscs, fish and crustaceans. This place has been recognized as a protected UNESCO site since 2015 and can be observed at low tide from a number of look-out points from nearby hiking trails.