The exterior aspect of all cathedrals is severe and massive, even naked and solemn. Neither windows nor flying buttresses are used in such profusion as in French cathedrals, and the height of the aisles is greater. The object is doubtless to impart an idea of strength to the exterior walls by raising them in a compact mass. An even greater effect is obtained by square, heavy towers instead of elegant spires. (Compare, however, chapters on Leon, Oviedo, Burgos, etc.) The use of domes (_cimborios_, lanterns, and cupolas) is also frequent, most of them being decidedly Oriental in appearance. The apse is prominent and generally five-sided, warlike in its severe outline. Stone is invariably used as the principal constructive element,--granite, _berroqueña_ (a soft white stone turning deep gray with age and exposure), and _sillar_ or _silleria_ (a red sandstone cut into similar slabs of the size and aspect of brick). Where red sandstone is used, the weaker parts of the buildings are very often constructed in brick, and it is these last-named cathedrals that are most Oriental in appearance, especially when the brick surface is carved into _Mudejar_ reliefs. Taken all in all, the whole building often resembles a castle or fortress rather than a temple, in harmony with the austere, arid landscape, and the fierce, passionate, and idolatrous character of the clanspeople or inhabitants of the different regions. The principal entrance is usually small in comparison to the height and great mass of the building. The pointed arch--or series of arches--which crowns the portal, is timid in its structure, or, in other words, is but slightly pointed or not at all. The interior aspect of the church is totally different. As bare and naked as was the outside, so luxurious and magnificent is the inside. Involuntarily mediæval Spanish palaces come to our mind: their gloomy appearance from the outside, and the gay _patio_ or courtyard behind the heavy, uninviting panels of the doors. The Moors even to this day employ this system of architecture; its origin, even in the case of Christian churches, is Oriental. Leaving aside all architectural considerations, which will be referred to in the chapters dedicated to the description of the various cathedrals, let us examine the general disposition of some of the most interesting parts of the Spanish church. The aisles are, as a rule, high and dark, buried in perpetual shadow. The lightest and airiest part of the building is beneath the _croisée_ (intersection of nave and transept), which is often crowned by a handsome _cimborio_. The nave is the most important member of the church, and the most impressive view is obtained by the visitor standing beneath the _croisée_.