From the orbit of its moon, the planet looks almost normal. Green and brown continents, jewel-blue oceans, swirling clouds. 

 

It's only up closer, above the larger of the two continents, that the devastation is evident. Whatever happened here, it left two enormous craters, each hundreds of miles across. One appears to be slowly filling with water; the other is an arid plain, where nothing grows but grass. The two craters are close to a thousand miles apart, sprawled on an approximately north-south line, inside an even bigger ellipse of ruin. Vast areas are blackened, deforested by forest fires that must have run wild for hundreds of miles. Some patches appear to have been slagged down to the glassy bedrock. Much of the terrain still has plant life, but it can't be called intact; the colors are wrong, too many purples and sinister oranges, not at all like the healthy green on the other continent. 

There are odd - circles? - that seem to not match their surroundings. Circles of flat grass in the middle of hilly scrubland. Circles of tall trees that neatly cut off rivers or pop up in the middle of lakes. The circles are in a pattern. To a clever eye, it's noticeably the pattern of amplitude-peaks that you get from the wave interference of two waves emanating from point sources some distance apart, and the origins match the location of the craters. 

There are signs of civilization. On the far western coast, separated by the spine of a long mountain range running north-south, there appears to be some kind of island-based empire, with fleets of merchant ships bustling up and down the whole coastline. The far southern edge of the continent is also mostly intact, though at a closer glance everywhere shows the signs of recent earthquakes, buildings collapsed and not yet repaired. 

The area east of the destruction lacked a protective mountain range and is correspondingly worse-hit. And also, judging by the patchy brown-yellow and the lakes noticeably retreating inward from their former banks, suffering a major widespread drought that must have lasted many years. But there are a few areas of green, arranged in a way that looks like farming at work. 

Northeast, backed up against the northern, icebound mountain range, is an area several hundred miles across which for some reason inexplicably has an enormous magical force-field around it??? 

There are people living in the southern crater, the one that's not on its way to becoming a lake. They have horses and herds of livestock and tents. No buildings.

There are also people living in much smaller and fainter magical-force-field-bubbles, nestled near the periphery of - but still within - the worst-hit areas.