The German architects delighted in towers with pointed roofs, and in a multiplicity of them. A highly characteristic feature is a tower of great mass, but often extremely low, covering the crossing. The Cathedral at Mayence shows a fine example of this feature, which was often not more than a low octagon. Western towers, square on plan, are common, and small towers, frequently octagonal, are often employed to flank the choir or in combination with the transepts. These in early examples, are always surmounted by high roofs; in late ones, by stone spires, often of rich open tracery. A very characteristic feature of the round arched Gothic churches is an arcade of small arches immediately below the eaves of the roof and opening into the space above the vaults (Fig. 45). This is rarely wanting in churches built previous to the time when the French type was followed implicitly. The gables are seldom such fine compositions as in France, or even in Italy; but in domestic and secular buildings many striking gabled fronts occur, the gable being often stepped in outline and full of windows. _Roofs and Vaults._ Vaults are universal in the great churches, and German vaulting has some special peculiarities, but they are such as hardly come within the scope of this hand-book. Roofs, however, are so conspicuous that in any general account of German architecture attention must be paid to them. They were from very early times steep in pitch and picturesque in outline, and are evidently much relied upon as giving play to the sky-line. Indeed, for variety of form and piquancy of detail the German roofs are the most successful of the middle ages. The spires, as will have been easily gathered from the descriptions of those at Strasburg, Cologne, &c., became extremely elaborate, and were constructed in many cases entirely of open tracery. [Illustration: FIG. 47.--WESTERN DOORWAY OF CHURCH AT THANN. (14TH CENTURY.)] [Illustration: FIG. 48.--CHURCH OF ST. CATHERINE AT OPPENHEIM. (1262 TO 1439.)] _Openings._ Openings are, on the whole, treated very much as the French treated them. A good example is the western doorway at Thann (Fig. 47); but the use of double tracery in the windows in late examples is characteristic. Sometimes a partial screen of outside tracery is employed in other features besides windows, as may be seen by the very elegant doorway of St. Sebald's Church at Nuremberg, which we have illustrated (Fig. 49). _Ornaments._