The Chapel of Santa Cristina de Lena, situated on a hill overlooking the River Lena valley, is undoubtedly one of the main treasures of the Asturian Pre-romanesque Art, a unique style in the world. It was built in times of Ramiro I (842-850) or his successor Ordono I (850-866). Its structure differs from that of other churches raised by the Asturian Monarchy. It has a single rectangular nave with four small projections, also rectangular in shape, one in the centre of each exterior wall (portico, apse and side rooms). All the spaces are vaulted with barrel vaulting on transversal ribs and the building is reinforced with numerous buttresses outside.