As a principle of military defence the site was well chosen, for the barrier of the falls would prevent the approach of an enemy to the city by the river from the Atlantic. "The extent of the Ruins along the river, as ascertained by monuments still found, is _more than two miles_. There is one monument (or ruin) on the opposite side of the river, at the distance of a mile, on the top of a mountain two thousand feet high. Whether the city ever crossed the river, and extended to that monument it is impossible to say; I believe not." So do we,--and that belief instructs us in the seeming fact of another means of military defence; for from the locality and height of the mountain it is almost evident that the "monument" was used as a watch-tower, and consequently from that elevated point a complete view was obtained of all the approaches to the city. These facts illustrate (seemingly at least) that the Aborigines had a knowledge of military security as well as that of architecture; and as we believe that Copan was the first city built in the Western Hemisphere, these considerations will be of importance in identifying. The reader will understand ("once for all") that no hint, even the most remote, is derived from Mr. Stephens's work (or any other) towards the formation of our Theory, or the establishing of this Epoch,--on the contrary, he distinctly asserts (vol. ii., p. 442), "I shall not attempt to inquire into the origin of this people, from what country they came, or when, or how; I shall confine myself to their works and their ruins." Our artistical or historical comments, good, bad, or indifferent, are our own, and accompany the quotations for the purpose of supporting the Analogies in a subsequent chapter. The italicised and bracketed words the reader will give especial attention to;--as we have so expressed them for facility in illustrating.