The Spaniards retreated beyond the valley to their allies, the Tlaxcalans, at Cholula. Reinforcements and supplies arriving, they returned a few months later and began the memorable siege of Tenochtitlan, and made a triumphal entry into that city on the 13th of August, 1521. Then Guatemotzin, the last of the Aztec emperors, wept in his turn, because the sacred fires of the temple had for ever gone out, and his people would henceforth be slaves. “Take that dagger,” he said, “and free this spirit.” But, no, torture must come before death, for Cortez fain would learn where the gold was hidden that had so suddenly disappeared. To-day, in the City of Mexico, a statue stands in one of the circles of the famous Paseo, which commemorates this great warrior and his torture by the Spanish chieftain. This monument is greatly cherished by the Indians, who hold annual festivals in his honour and decorate it with a profusion of flowers and wreaths. The great Valley of Mexico is without a natural outlet, and this fact has caused seven inundations of the capital during exceptionally rainy seasons. One of the lakes, Zumpango, is twenty-five feet higher than the city and drains into Texcoco, from which the waters spread over the city. When the first serious inundations came in 1553, 1580 and 1604, the project of removing the city to a higher level was strongly agitated. It was only the loss of millions of dollars of property that prevented this action. Then the idea of draining this valley was definitely adopted and the work was begun in 1607. A tunnel was decided upon and fifteen thousand Indians were set at work sinking shafts and driving the tunnel in both directions. Within a year a tunnel four miles long had been completed. This tunnel eventually caved in, so that very little good was realized from it and efforts were made to convert it into an open cut. But this undertaking was not finished until two centuries later. It is a great trench, however, with an average depth of from one hundred and fifty to two hundred feet, and from three hundred to seven hundred feet in width at the top. It is called the _Tajo de Nochistongo_, or Nochistongo cut, and its only use now is as an entrance for the Mexican Central railway. Even this waterway did not drain the valley, remarkable engineering feat as it was, but a new canal was constructed by American engineers a few years ago which successfully accomplishes the work of draining these shallow lakes and carrying off the sewerage of the city.