You've heard about terrorist groups like ISIS and the Taliban destroying irreplaceable historic sites all across the Middle East. It's heartbreaking to watch as they destroy treasures, ancient sculptures and remarkably well-preserved cities that people have seen for millennia.
How could they do that? How can we let them get away with it?
Of course, technology can help. Not for the lost treasures, but to preserve the ancient sites that we've still got.
That is already well underway in Peru, where the magnificent, 600-year-old mountaintop city Machu Picchu is being preserved, one photograph at a time.
For the past couple years, Peru's Ministry of Culture has been flying drones over the ancient city. On each 15-minute drone flight, they take still photographs of small pieces of the huge complex, from 200 feet up. Then, they string those photos together into a complete 3-D image of Machu Picchu.