Smack in the city centre is Robert Koch Hill, with an attractively decrepit German-built mansion at the top. Several Maasai now live here, but if you introduce yourself and give them a small donation (Tsh5000 should be okay), you can look around. To get here, push through the bustling market, and take the trail through the beer garden and past all the piles of rubbish. You shouldn't go up there late in the day and single women shouldn't go alone.