KARACHI, PAKISTAN—Archaeologists say that the wooden and steel scaffolds erected at Mohenjodaro to serve as a stage for the launch a cultural heritage festival have harmed the ancient site, and that a planned light and sound show could further damage its delicate walls. “You cannot even hammer a nail at an archaeological site,” commented Farzand Masih of Punjab University. He added that the country’s Antiquity Act banned such activities. Mohenjodaro was one of the largest cities in the Indus Valley some 5,000 years ago.