Landscape of the Martín River in Híjar Nature · Híjar, Bajo Martín, Teruel The river Martín, a tributary of the Ebro, forms a distinctive valley next to the town centre of Híjar; three irrigation channels drawn from the so-called Gaén irrigate about 1,450 cahizadas of market garden that historically produced grain, wine, oil and hemp. Photo: Wikipedia / Wikimedia Commons (CC BY-SA) What to see and do in Híjar