Without the Canals. Olympus Mons is circle on upper center.
Valles Marineris is vertical gash on right.
Valles Marineris from the Mars Express spacecraft. (NASA)
Iron beads ("Mars berries") indicate history of water
In 1877 the Italian Astronomer Giovanni Schiaparelli observed what he called “canali”, deep straight channels crossing the surface of Mars. This dubious observation was enthusiastically endorsed by astronomer Percival Lowell in 1894, claiming that such man-made canals carrying water across the arid surface were clearly a sign of intelligent life on a nearby planet. For a world that had recently completed the Suez Canal (1869), and struggled with a similar attempt to build a passage across Panama (abandoned by the French in 1889), what could be more encouraging than the idea of another civilization with similar engineering goals. We are not alone. Although the theory of canals on Mars was widely discredited, it continued to dominate our imagination. H. G. Wells (War of the Worlds, 1894) proposed a dying planet of plant-like creatures attacking Earth mainly for the water. Robert Heinlein in The Green Hills of Earth (1947) portrayed Mars as a corrupt world where ugly factories had polluted the once-beautiful canals. A good fantasy never goes away. Even today there is a web site that wonders aloud if the disappearance of those great canals over the last century is not a sign of some cosmic catastrophe.
Although Mars is smaller than Earth, its terrain is much more dramatic. Olympus Mons is three times the height of Mt Everest. Valles Marineris is seven times deeper than the Grand Canyon and 2000 miles long. Signs of erosion suggest that the planet must have had rivers, lakes and layers of ice on its surface about 4 billion years ago, and there are still polar ice caps there today. But without vegetation to create a protective layer of greenhouse gasses, the planet is cold (43° F) and dry. The air is mostly unbreathable carbon dioxide and the surface is swept by giant duststorms that cover the entire planet for months. There is no evidence of life.
If you like mazes, here's the hardest one we know. It was written by Lewis Carroll (English writer and mathematician Charles Dodgson, 1832-1899) to entertain and mystify his ten younger brothers and sisters. Poor Alice is trapped in the center of a labrynthian wood, and must follow one of the twisting paths to freedom. Unlike normal mazes, these paths go over and under each other by means of tunnels and bridges, and once in a while they meet a barrier that cannot be crossed. In the Victorian Age people actually built mazes out of hedges, earth and even high grass and corn, but none were as complex as this. Good luck.
