supposed linear features on Mars. The Italian word canale, meaning simply channel, was used in the nineteenth century by Angelo Secchi to describe linear features he perceived during observations of Mars, and later by Giovanni Schiaparelli. The word was translated into English as canal with the connotation that what had been observed were artificial structures. The notion was elaborated by Percival Lowell, who built an observatory at Flagstaff, Arizona, with the main purpose of observing Mars. His drawings of the planet showed extensive networks of linear canals, and he proposed that a civilization of intelligent beings on Mars was responsible for constructing them. Later observers have found little evidence of such markedly linear features, and Mariner and Viking images show no trace of them; they are now dismissed as optical effects.