Taoudenni

But salt can be used to cure and preserve meat despite the heat.

One of the historic trade networks still traveled by the Tuareg begins near Mali's great Taoudenni salt mine and ends more than four hundred miles, six hundred and forty-four kilometers, away in Timbuktu.

Trading salt.

The Taoudenni salt mine is the greatest source of salt in the Sahara.

Camel caravans leave the mine with slabs of salt, often covered with mud that is allowed to dry.

The hardened mud protects the slab from being battered to bits by windblown sand and from dissolving should rain happen to fall.

They often stop at many of the same oases that they had passed through on their way south.

The oasis-dwelling people of the desert are happy to receive agricultural produce and handicrafts from Timbuktu.

And Lake Chad wasn't unique to the west in what is now Mauritania and Mali.

Geomorphologists have identified shorelines and sediment deposits pointing to another giant lake system in the Taoudenni basin.

To the east, depressions in Libya and Egypt, places like the Kufra and Dakhla basins, show layered lake sediments, fossil shells, and muds with freshwater organisms that simply shouldn't exist in the middle of a hyper-arid desert unless those basins once held water.

Some of these mega lakes were probably more like clusters of broad, shallow, interconnected basins than single deep bowls.