Reserva de la Biosfera de Urdaibai Nature · Busturia, Gernika-Bermeo, Bizkaia The Oka estuary and its surroundings were declared a Biosphere Reserve under UNESCO's MaB program in 1984, covering 22,452.38 hectares (around 10% of the territory of Bizkaia). It includes estuary, salt marsh, Cantabrian holm-oak woods, oak groves, Atlantic meadows and sand dunes, and wholly or partly encompasses 22 municipalities (including Mundaka, Sukarrieta, Busturia, Murueta, Forua, Gernika-Lumo, Ajangiz, Mendata, Arratzu, Kortezubi, Gautegiz Arteaga and Elantxobe). The wetland was also included in the Ramsar Convention on wetlands of international importance in 1992 (943 hectares) and has been part of the Natura 2000 network as an SPA since 1994. 1984 (declaración UNESCO); 1992 (Ramsar); 1994 (ZEPA) Photo: Txo (Public domain) What to see and do in Busturia