La Concha Promenade The bay on the coast of Gipuzkoa, shell-shaped as indicated by its name in Spanish, home in a semi-circle to the Ondarreta and Concha beaches; it runs from Mount Igeldo to Mount Urgull and has an Island in the centre, Santa Clara. The famous white railings that skirt the entire promenade, work of Juan Rafael Alday, have become the single best-known feature of San Sebastián.