One day we reached the edge of the sea. The salt water lapped up onto a 
lifeless beach strewn with the bones of extinct sea creatures, from tiny 
trilobites all the way up to
plesiosaurs. Behind us was the desert we'd just crossed. To the south was a 
range of mountains that would have been impassable even if half of them hadn't 
been erupting volcanoes. And north of us we could see snow dusting the tops of 
the hills, and we all knew what that meant: If we went in that direction, we'd 
soon freeze to death.