During the night, a tremendous tempest, such as the Spaniards had rarely witnessed, and such as is known only within the tropics, burst over the Mexican Valley. The thunder, reverberating from the rocky amphitheatre of hills, bellowed over the waste of waters, and shook the _teocallis_ and crazy tenements of Tenochtitlan--the few that yet survived--to their foundations. The lightning seemed to cleave asunder the vault of heaven, as its vivid flashes wrapped the whole scene in a ghastly glare, for a moment, to be again swallowed up in darkness. The war of elements was in unison with the fortunes of the ruined city. It seemed as if the deities of Anahuac, scared from their ancient abodes, were borne along shrieking and howling in the blast, as they abandoned the fallen capital to its fate![129] On the day following the surrender, Guatemozin requested the Spanish commander to allow the Mexicans to leave the city and to pass unmolested into the open country. To this Cortés readily assented, as, indeed, without it he could take no steps for purifying the capital. He gave his orders, accordingly, for the evacuation of the place, commanding that no one, Spaniard or confederate, should offer violence to the Aztecs or in any way obstruct their departure. The whole number of these is variously estimated at from thirty to seventy thousand, besides women and children, who had survived the sword, pestilence, and famine.[130] It is certain they were three days in defiling along the several causeways,--a mournful train;[131] husbands and wives, parents and children, the sick and the wounded, leaning on one another for support, as they feebly tottered along, squalid, and but half covered with rags, that disclosed at every step hideous gashes, some recently received, others festering from long neglect, and carrying with them an atmosphere of contagion. Their wasted forms and famine-stricken faces told the whole history of the siege; and, as the straggling files gained the opposite shore, they were observed to pause from time to time, as if to take one more look at the spot so lately crowned by the imperial city, once their pleasant home, and endeared to them by many a glorious recollection.