The ancient deserts of Mars are broken up in the south by the last remnants of the planet's dwindling seas. In the north, the canals and the narrow strips of vegetation running along their banks precisely cut a vast network of lines and arcs through the low mountains and across the ochre wastes. No other evidence of Martian civilization remains as visible from offworld. Whatever their fate, the Martians met it long ago.
At its height, Martian civilization must have dotted the planet with cities as it does today's Earth, clustered at canal intersections and sprawling along the coasts. Often, canals end in, or run through, massive reservoirs that likely mark the former site of a Martian metropolis. The ruins themselves, if they survive, are now visually indistinguishable from the surrounding terrain. They may be buried in sand, thoroughly overgrown, or simply crumbled to dust ten thousand years ago. The canals were built to last. The overwhelming majority of them remain perfectly navigable to this day. In some areas, however, their walls have eroded to a scalloped appearance, and in a few places this erosion has progressed so far that the canal floor is now blocked with sediment.
For human colonists, simply clearing a blocked canal would be a monumental achievement. While no human has yet set foot on Mars, one could hardly find a more welcoming planet. The air is breathable despite the relatively sparse plant life. Polar melt supplies the deserts with water via the northern canals, which provide a ready-made transport network just as the ancient Martians would have used them. While the cause of their extinction remains unclear, one thing is certain: should a future civilization take root here, it will grow in the Martians' image.
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