Pakistan, which gets about a third of its power from from hydro-electrcitiy, is planning to build a $12bn dam in an effort to get power to the rugged northern regions. But it means blocking the Indus River, in the valleys of Baltistan. That would flood villages 40kms upstream and force tens of thousands of people to leave their homes in the shadow of one of the world's great mountains. Al Jazeera's Kamal Hyder reports (28 Mar 2010).