Challenging was considered a temperate and beautiful planet by Human standards, with a varied terrain that included coastal lakes and tar-pits, thick forests and snow-capped mountain peaks, powerful rivers and broad savannas, small icecaps and dramatic rift valleys. Even under the King Cold, however, nine-tenths of the planet remained unexplored and uninhabited, with the population limited to a relatively small area along the edge one of the three main continents, a zone of uplands and river plains bounded on one side by the un-sailed ocean and on the other by vast expanses of desert.