Isabel Urquiola Estala (1854-1911) was a Spanish explorer who in 1874 accompanied her husband Manuel Iradier and her younger sister Manuela (or possibly Juliana) on an expedition to Africa. While Iradier travelled some 1,900 km from Corisco Bay up the Muni River, hoping to reach the Spanish colonies in the African interior, the two sisters remained on the island of Elobey Chico during his absence. Today Isabel Urquiola and her sister are remembered for the meticulous meteorological data they recorded while spending some eight months on the island. Isabel Urquiola never recovered from her experiences in Africa, having lost a child there and suffered from fever.