What can I do in Morocco in 8 days?

Eight days is a genuine threshold. Below it, adding Fes wrecks the pacing; at eight, the famous Marrakech-Sahara-Fes line finally works because you can do it one-way instead of looping back over your own tracks. You arrive in Marrakech, sweep south and east through the desert, then climb north to Fes and fly home from there. No backtracking, no wasted days.

I'd run it like this. Two nights Marrakech to open — medina, Bahia Palace, Majorelle, the souks. Then the southern drive: Tizi n'Tichka, Ait Ben Haddou, a night in the Dades or Todra gorge, and on to Merzouga for a night in the dunes with camp dinner and stargazing. From the desert you cross via Midelt and the cedar forests of the Middle Atlas — keep an eye out for the Barbary macaques — and drop into Fes.

Fes is where eight days earns itself. Give it two full nights and a local guide, because the medina is a 9,000-lane labyrinth and you'll otherwise spend your time lost rather than looking. The tanneries, the Al-Qarawiyyin, the metalworkers' square, the artisan workshops, a long mint-tea pause on a rooftop above the chaos — Fes rewards slowness in a way Marrakech doesn't, and it's the city most travellers end up loving most.

I'd consciously leave the Atlantic coast out of an eight-day plan. Essaouira or the surf towns pull you west, exactly the wrong direction for a Marrakech-to-Fes line, and squeezing them in would mean cutting the desert short or losing a Fes night. Eight days is two great cities and the Sahara, properly. The coast is what you add when you stretch to eleven or twelve.