From the cliffs on the opposite sides of the barranca, two huge trees shot up to an enormous height, and, inclining towards each other, interlaced their boughs so as to form a sort of natural bridge. Across this avenue, in mid-air, a Tlascalan conceived it would not be difficult to pass to the opposite bank. The bold mountaineer succeeded in the attempt, and was soon followed by several others of his countrymen, trained to feats of agility and strength among their native hills. The Spaniards imitated their example. It was a perilous effort for an armed man to make his way over this aerial causeway, swayed to and fro by the wind, where the brain might become giddy, and where a single false movement of hand or foot would plunge him in the abyss below. Three of the soldiers lost their hold and fell. The rest, consisting of some twenty or thirty Spaniards and a considerable number of Tlascalans, alighted in safety on the other bank.[371] There hastily forming, they marched with all speed on the city. The enemy, engaged in their contest with the Castilians on the opposite brink of the ravine, were taken by surprise,--which, indeed, could scarcely have been exceeded if they had seen their foe drop from the clouds on the field of battle. They made a brave resistance, however, when fortunately the Spaniards succeeded in repairing one of the dilapidated bridges in such a manner as to enable both cavalry and foot to cross the river, though with much delay. The horse, under Olid and Andres de Tápia, instantly rode up to the succor of their countrymen. They were soon followed by Cortés at the head of the remaining battalions, and the enemy, driven from one point to another, were compelled to evacuate the city and to take refuge among the mountains. The buildings in one quarter of the town were speedily wrapped in flames. The place was abandoned to pillage, and, as it was one of the most opulent marts in the country, it amply compensated the victors for the toil and danger they had encountered. The trembling caciques, returning soon after to the city, appeared before Cortés, and deprecating his resentment by charging the blame, as usual, on the Mexicans, threw themselves on his mercy. Satisfied with their submission, he allowed no further violence to the inhabitants.[372] Having thus accomplished the great object of his expedition across the mountains, the Spanish commander turned his face northwards, to recross the formidable barrier which divided him from the Valley. The ascent, steep and laborious, was rendered still more difficult by fragments of rock and loose stones, which encumbered the passes. The mountain sides and summits were shaggy with thick forests of pine and stunted oak, which threw a melancholy gloom over the region, still further heightened at the present day by its being a favorite haunt of banditti.