Khartoum to El Aaiun

In the spring of 1973, aged 19, Mark Goodwin volunteered to teach English and Maths at a school in South Sudan. Upon arrival in Khartoum, he was informed that ‘some troubles had begun’ and he was not allowed to travel south. With time on his hands, how hard could it be to go west from the Nile to Nigeria and then cross the Sahara before returning to England? In a time before credit cards and mobil...