National Geographic : 1930 Jul
NORTH AMERICA'S OLDEST METROPOLIS Photograph by Clifton Adams HOLIDAY THRONGS CELEBRATE HOLY WEEK IN MEXICO By day and night processions commemorate the successive parts of the Easter story. Effigies of Judas are burned on Good Friday and elaborate ceremonies are conducted in all the churches. This crowd in the Indian market in the Alameda is buying toys and fireworks. land, and a waterway for canoes and barges ran out to Lake Texcoco. Floods were so bad, even before the Spaniards came, that the Aztecs had built dams, and as early as 1553 the Viceroy Luis de Velasco struggled with the prob lem. FLOOD HAZARD NOW CONTROLLED One gigantic trench-the still famous Tajo de Nochistongo-was begun in 1607, in which task thousands of overworked Indians perished. It was first opened as a tunnel to drain the valley lakes; then, closed in a dispute, flood waters rose three feet deep in the city streets. Changed later from a tunnel into a great trench, in places o10 feet deep and 300 feet wide, the Tajo de Nochistongo remains an amaz ing example of what early Spaniards could do with Indian slave labor. From your train you can see this historic man-made mountain pass now, as you ride into Mex ico City from the north. One of the strangest aspects of Mexico City is that, though perched so high up near a continental divide, it long diked and drained itself like a seaside town in Hol land. It was not till 1900, after centuries of study and work, that the city was made safe, when the great 30-mile Canal del De sagiie was completed. On it thousands of men worked for years, with teams, trams, and steam shovels. It is easily the most spectacular modern engineering feat from the Roosevelt Dam to the Panama Canal. To dig this ditch and carry its tunnel to more than six miles, under the Xalpan Mountains, nearly II,ooo,ooo cubic meters of earth and rock had to be moved. With lock gates, waste water is now controlled and Lake Texcoco held at a safe level, so no more floods may swamp Mex ico City; but underground the water is still at work. You need no plumb bob or spirit level, when you look at some heavy old buildings in the city, to see that they are leaning from the perpendicular; and some are sinking so badly as to threaten collapse. This slow subsiding of heavy structures is due to the swampy soil on which the city stands.