The salt pans are the reason Bilma is here. A patchwork of shallow rectangular brine pools — some clear, some red, some green with algae — spreads east of the town for a couple of kilometres, worked by Kanouri families who have done this work for generations. The pools are fed by salty springs; the water evaporates in the sun, and the residue is scraped into wooden moulds to make the distinctive cone-shaped blocks of salt.
It is one of the few places left in the Sahara where you can watch a pre-industrial economy still operating on its original terms. A polite request to the workers (and ideally a small payment via your guide) will usually get you a closer look. Wear sturdy shoes — the crust along the pools' edges is fragile and uneven.