Cortés had now reached the end of the great avenue, where it entered the suburbs. There he halted to give time for the rear-guard to come up with him. It was detained by the labor of filling up the breaches in such a manner as to make a practicable passage for the artillery and horse and to secure one for the rest of the army on its retreat. This important duty was intrusted to the allies, who executed it by tearing down the ramparts on the margins and throwing them into the chasms, and, when this was not sufficient,--for the water was deep around the southern causeway,--by dislodging the great stones and rubbish from the dike itself, which was broad enough to admit of it, and adding them to the pile, until it was raised above the level of the water. The street on which the Spaniards now entered was the great avenue that intersected the town from north to south, and the same by which they had first visited the capital.[9] It was broad and perfectly straight, and, in the distance, dark masses of warriors might be seen gathering to the support of their countrymen, who were prepared to dispute the further progress of the Spaniards. The sides were lined with buildings, the terraced roofs of which were also crowded with combatants, who, as the army advanced, poured down a pitiless storm of missiles on their heads, which glanced harmless, indeed, from the coat of mail, but too often found their way through the more common _escaupil_ of the soldier, already gaping with many a ghastly rent. Cortés, to rid himself of this annoyance for the future, ordered his Indian pioneers to level the principal buildings as they advanced; in which work of demolition, no less than in the repair of the breaches, they proved of inestimable service.[10] The Spaniards, meanwhile, were steadily, but slowly, advancing, as the enemy recoiled before the rolling fire of musketry, though turning, at intervals, to discharge their javelins and arrows against their pursuers. In this way they kept along the great street until their course was interrupted by a wide ditch or canal, once traversed by a bridge, of which only a few planks now remained. These were broken by the Indians the moment they had crossed, and a formidable array of spears was instantly seen bristling over the summit of a solid rampart of stone, which protected the opposite side of the canal. Cortés was no longer supported by his brigantines, which the shallowness of the canals prevented from penetrating into the suburbs. He brought forward his arquebusiers, who, protected by the targets of their comrades, opened a fire on the enemy. But the balls fell harmless from the bulwarks of stone; while the assailants presented but too easy a mark to their opponents.