In the late 19th century, several astronomers, including the respected Italian scientist Giovanni Virginio Schiaparelli, reported seeing dark, straight streaks across the surface of the planet. These “canali” or canals, as they became known, seemed to traverse much of the surface of the planet, and appeared to connect dark areas that observers believed were Martian oceans.
Schiaparelli published his first maps identifying the Martian canals in 1877. While there were a few dissenters, astronomers around the world began confirming Schiaparelli’s discoveries. With the discovery and mapping of the canals, speculation on the nature of life on Mars ran wild in the popular and scientific press. The canals, which some scientists estimated to be dozens of miles wide and thousands of miles long, appeared on most published maps of the planet.
Not all who looked found the canals, however. Even at the height of the Martian frenzy, there were observers who could not see the canals, and disputed their existence.
Although the “marvelous legend” of the Martian canals was discredited early in the 20th century, the imagined possibility that some form of hidden life flourishes on the red planet persists even today.