The Battle of Topater took place on 23rd March 1879 and was the first battle of the War of the Pacific. After the Chilean forces occupied Antofagasta they advanced on Calama where they met resistance from Bolivian troops and civilians, led by Eduardo Abaroa. The Chileans outnumbered the Bolivians and prevailed; Abaroa refused to surrender and was killed, becoming a national hero in Bolivia. The date and Abaroa's defiance is commemorated each year in Bolivia as Dia del Mar / Day of the Sea.