The Valley of Mexico is a region of somewhat remarkable topographical character. It consists of a plain or inter-montane basin, enclosed on all sides by ranges of hills, forming a hydrographic entity whose waters have no natural outlet.[15] A group of lakes occupy the central part of this valley, very much reduced, however, in size since the time of the Conquest. [Footnote 15: See p. 17.] [Illustration: THE LAKES OF THE VALLEY OF MEXICO AT THE TIME OF THE CONQUEST, SHOWING THE CAUSEWAYS TO THE AZTEC ISLAND-CITY OF TENOCHTITLAN. (From Prescott's "Conquest of Mexico.")] It was the 8th of November, 1519. Across the southern end of the great Lake Texcoco stretched a singular dyke or causeway, several miles in length and a few yards in width--a road or pathway built up of stone and mortar above the surrounding water, connecting the shores of that inland sea with an island and three other similar causeways. Upon this island arose a beautiful city with streets of strange buildings, above which rose great pyramids with sanctuaries upon their summits; and upon the bosom of the lake numerous canoes were plying, laden with men and merchandise. So rose those towers, and lived and moved the dwellers of this lake city, unknowing and unknown of European man, living their life as if no other world than theirs held sway beneath the firmament of the "unknown God." But the spell is broken. A trumpet sound is ringing through the morning air. Across the causeway comes a troop of strange men-animals--fearful things which snort and tramp, making the causeway rumble, whilst the notes of that strange music echo away among the towers and pyramids of the city, and are borne far over the waters of the lake, to smite the ears of wondering Indians. Cortes and his Spaniards rode steadily along the causeway, their hearts beating--as well they might--with astonishment, admiration, apprehension, and all those emotions to which their unique and romantic position gave impulse. Guided by the messengers of Montezuma, the white men rode beneath a fortification in mid-causeway, where another similar structure joined it from another shore of the lake, passed the drawbridge and the city walls, and clattered up the stone-paved avenue of Tenochtitlan to where, in pomp and splendour, surrounded by his lords and vassals, the great Aztec chief awaited them, in a royal litter gleaming with polished gold. Cortes and his men dropped foot to earth, and Montezuma descended from his litter. The Spaniard _Conquistador_, after the custom of his race, advanced to embrace the chief, "but," wrote Cortes to Charles V., "the two lords in attendance prevented me with their hands that I might not touch him, and both Montezuma and they performed instead their ceremony of kissing the ground."