Pozo de la Salud Monument · Frontera, El Hierro, Santa Cruz de Tenerife A spring at Sabinosa, drilled between 1702 and 1704, whose mineral-medicinal waters were officially recognised as such in 1843-1844; they were even bottled and exported to Cuba and Puerto Rico. perforado en 1702-1704; aguas declaradas mineromedicinales en 1843-1844 Photo: CARLOS TEIXIDOR CADENAS (CC BY-SA 3.0) What to see and do in Frontera