LIMA, Aug 26: In Peru, home to the spectacular Inca city of Machu Picchu and thousands of ancient ruins, archaeologists are turning to drones to speed up sluggish survey work and protect sites from squatters, builders and miners. Remote-controlled aircraft were developed for military purposes and are a controversial tool in US anti-terrorism campaigns, but the technology’s falling price means it is increasingly used for civilian and commercial projects around the world. (agencies)