Bridge over the Gállego in Biescas Monument · Biescas, Alto Gállego, Huesca Image of Biescas, not of the place itself. The Puente del Diablo of Biescas, over the river Gállego, is attributed to the architect Juan Albistur in 1559 and formed part of the royal road linking Biescas with Santa Elena; legend has it that the devil himself built it in a single night. Photo: Jean Michel Etchecolonea (CC BY-SA 3.0) What to see and do in Biescas