Embalse de Orellana en Orellana de la Sierra Nature · Orellana de la Sierra, Vegas Altas, Badajoz Image of Orellana de la Sierra, not of the place itself. The municipal term of Orellana de la Sierra borders the Orellana reservoir, covering 42,600 hectares, the largest in the middle Guadiana and a key element in the region's water management. Photo: Adolfobrigido (CC BY-SA 4.0) What to see and do in Orellana de la Sierra