South choir aisles looking east

Amiens, like Chartres and Reims Cathedrals, has a double choir aisle with two corridors of space vaulted at the same height, creating the impression of a "hall church." The intermediary piers are very slender and clad in a cage of 8 colonnettes which receive the transverse arches and ribs of the vaults above. The outer wall has a dado (blind arcade) at the lowest level and enormous aisle windows above. The outer wall of the nave aisles originally looked just like this. The existence of a double aisle created problems in the design of the flying buttresses above (invisible here) since the intermediary supports of the flyers sit atop the slender piers. We will see that the builders were forced to deploy a new kind of light-weight flyer.