Misc

Split Evolution
Humans on Mars evolve in small ways to better conform to the conditions on Mars. Reduced gravity means they are slightly taller, on average, than Earthlings. It also means lower muscle density for Martians, meaning they would struggle to withstand Earth's slightly stronger gravity.

Music
This is the key piece to keeping humans sane in the relentless isolation of space. The familiar sounds keep humanity grounded in a sense of community. New genres also are formed by the cultural development of Mars.

Sky/Water Red Shift
Color is determined by wavelength. Mars' atmosphere requires light to bounce around more (refraction) and causes a consistent red shift in the sky color. This also gives water a red shift since it's color is determines by similar processes.