Ok i have always wondered this, but have been a bit afraid to ask. Forgive me if this sounds completely stupid, impossible or unrealistic. Where there are regions affected with extreme drought e.g. Chad or Sudan, isn't possible to construct and build a massive underground water supply pipe or water supply network?????, so that these regions would be able to recieve water? I was thinking that a underground pipe could collect water from surrounding oceans or seas and this water could be cleaned whilst in the pipe and be turned into safe drinking water for the drought affected regions. Obviously this plan has some massive design or construction flaws or it would have already been builit. So what's wrong with this idea????