For one reason or another, people decided long ago to name all the important places on Mars using Latin words. In fact, the whole planet wears the name of the Roman God of War, so the choice of keeping with tradition might have seemed like a natural one.
Humans didn’t really get to understand just how peculiar (and alien) Mars really is until a flood of images of the planet started coming our way not long ago. Devoid of life, the place still manages to surprise time and time again with the strange features that are spread all over its surface, many of them quickly put in weird context by our imaginative brains.
There are a number of “biggest” features that can be found on Mars. Some are the biggest in the solar system, like the Valles Marineris, the longest and deepest canyon we know of, or the Hellas Planitia, a Western Europe-sized impact crater, and the largest one we’ve noticed so far.
By definition, asteroid impacts are incredibly violent events. Here on Earth, the average speed with which rocks from space hit is estimated at 40,000 mph (64,300 kph), but that’s mostly on account of our planet having a thick-enough atmosphere to slow things down a bit.
Generally speaking, impact craters turn out circular in shape, hence easily recognizable. There are times though when, depending on a lot of factors, including angle of impact and the topography of the terrain, that’s not what we get.