Playa de Sopelana

Sopelana is on the Basque coast twenty minutes from Bilbao by metro, which is unusual — few surf beaches anywhere are on an underground line. Three beaches sit below the town, separated by headlands of layered rock, and at low water two of them join into a single strand and part again as the tide fills.

The rock is the reason geologists come. This coast exposes flysch — alternating layers of hard and soft marine sediment, tilted almost vertical and eroded into blades — recording continuous deposition over roughly sixty million years. A few kilometres east at Zumaia the sequence includes the Cretaceous–Palaeogene boundary, the thin layer marking the asteroid impact that ended the dinosaurs, and it is one of the best exposures of it in the world.

The beaches are golden sand with real Bay of Biscay swell, and this is a serious surf coast. Rip currents are present, lifeguards patrol in season, and the tidal range is large enough that the beach roughly doubles at low water. Barinatxe, between Sopelana and Getxo, is a long-established naturist beach. The clifftop path runs east toward Getxo and west toward Barrika past the whole flysch sequence, and it is walkable in sections between metro stops.

Development is a town on the clifftop with stairs and a lift down. The Basque coast is green, wet and mountainous, and the water is cold — around 21°C in late summer and 12°C in winter. Mundaka's left, forty minutes east, is one of Europe's best-known waves and breaks over a sandbar at a river mouth.

Twenty minutes from Bilbao on the metro, which is not a sentence many surf beaches can offer. The flysch cliffs record sixty million years of deposition and the same sequence at Zumaia holds the layer left by the asteroid. The tide roughly doubles the sand and the rips are real.