Era Kohor is the enormous natron crater plunging some hundreds of metres into the western flank of Emi Koussi, its pale floor encrusted with salt and natron and known to French geographers as the Trou au Natron. In Teda regard it is a place of dread, held to be the haunt of dangerous spirits and shunned by travellers who pass along its rim. The crater's abyssal depth, its trapped heat and its glaring white bed set it apart as one of the most forbidding features of the range. Its name is variously reported, Era Kohor and Doon among them, and its exact etymology is not settled in the ethnographic record.