I'm in Egypt at the moment. We're in Dahab, on the Sinai peninsular - but we spent several weeks travelling on the Nile from Cairo to Aswan and Luxor before we got here.

The experience that really brought home the importance of the Nile was taking the overnight train from Cairo to Aswan. You wake up in the morning to sunrise over the Nile. If you look out of the left hand window of the train, you see desert - nothing but sand and rocks. If you look out of the right hand window, you see literally just a few hundred metres of lush green farmland followed by the expanse of the river. It makes you realise that a large chunk of Egypt's usable land is hundreds of miles long but less than half a mile wide.