Video: Pakistan World Heritage site Mohenjodaro 'crumbling to dust' Mohenjodaro, which means "the mound of the dead' was a major centre of the pre-Hindu Indus civilisation dating back to 3000 BC. The city was remarkably advanced for its time, with sophisticated civil engineering and urban planning and due its size and the richness of its monuments has been generally regarded as a capital of an extensive state. The city was rediscovered in 1922. Significant excavation has since been conducted at the site of the city, which was designated a UNESCO World Heritage Site in 1980. However the ruins are constantly besieged by the area's hostile elements. Soaring temperatures, winter frosts, torrential rains and humid air all combine to leave the ancient sun-dried clay bricks with a dusting of white salt crystals which dry them out and cause them to crumble dust. Telegraph's South Asia editor Dean Nelson reports how the site could disappear within 20 years without an urgent rescue plan.