Juxtaposing one engineering feat with another, William Henry Jackson made this photograph of a railroad engine passing beneath an arch of an aqueduct, sixty-nine feet high. The aqueduct, which provides water for the city of Querétaro in central Mexico, was built between 1726 and 1738, but the railroad did not arrive there until a hundred and fifty years later, in 1886. A close study of the image reveals a porter standing in the open doorway of the first car and a number of youthful passengers leaning out the windows of the rear car. In any city, the arrival of the railroad was invariably a cause for celebration; Jackson's photograph commemorates the introduction of this new method of transportation in the context of an earlier achievement.