Once the envy of the rest of Pakistan, Shangla district in the north had all the cheap electricity its inhabitants could consume, thanks to the ingenuity of local entrepreneurs who harnessed the power of rivers.

But the devastating monsoon floods which hit the country in August have swept away the infrastructure, plunging Shangla into darkness and turning back the clock many decades, finds the BBC's M Ilyas Khan.

"This is where my furniture factory stood. It was about 30ft above the river, and several dozen feet away from it," says Farmanullah, a businessman in northern Pakistan's Khyber-Pakhtunkhwa province.

But for about 200ft (60m) on either side of where he is standing, in the village of Damorai in Shangla district, it's now a vast bed of rocks and boulders.