The elevation is in three stages, arcade, triforium gallery and clerestory. Sometimes another gallery set into the wall space above the triforium and below the clerestory. Above the nave is a triforium containing double Norman arches. Saint-Maclou has the classic three-story elevation of an arcade, triforium, and clerestory. It follows a standard English Gothic plan, with a triforium and a very high clerestory. The nave's length was particularly notable, with a Norman triforium and vaulted ceiling. There is a triforium gallery with four cusped arches to each bay. The gallery above the narthex is at the level of the triforium. The side walls feature a triforium with pointed-arch stained glass windows. The triforium has a single large arch in each bay. The Queen's Diamond Jubilee Galleries have been created in the medieval triforium of the abbey. The triforium generally opens into space beneath the sloping roof of the aisle. A good example of a triforium is the Santiago de Compostela cathedral. The triforium (open arcade) above the door is unique in Scottish medieval architecture. The main arcade is topped by a string course below a triforium.