This street was built in the mid-nineteenth century across from El Pilar so that the central dome of the basilica could be seen from Calle Coso. It has preserved almost all the buildings of the 19th century. On the 12th of October every year thousands of people dressed in traditional costume bringing flowers to the Madonna El Pilar. The name of the street comes from the king of Aragón Alfonso I, who reconquered Zaragoza in 1118. This area is ideal for purchasing souvenirs and typical products.