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.
The Ministry of Culture is doing in just a few minutes what it would take researchers on the ground days, or weeks to do. By recording the entire site, they will be able to monitor any changes to it and, it's hoped, prevent horrific damage to Machu Picchu and other sites.
In 2013, for instance, a Peruvian developer intentionally knocked down a 4,000-year-old pyramid to build houses. Just this year, a man claimed a historic site as his own, then leveled it and put a fence around it.
Most ironic, last year, Greenpeace activists damaged Peru's incredible Nazca Lines. Those are the huge line drawings in the sand that stretch over 190 miles. You can see the whole images only from a plane. (Some people think aliens created them.)
The Greenpeace activists protested by placing huge, temporary letters onto one of the Nazca Lines drawings. They were protesting about using renewable energy. Since the letters were temporary, they were obviously trying to avoid damaging the site. Yet, they did just that by walking all over it as they put the letters down.
These days, Peru's Ministry of Culture is hoping they can stop swoop in and stop that type of damage, before it happens. But, if there is damage, they'll at least have a permanent, virtual 3-D record of the country's historical sites. Who knows, maybe someday you'll be able to visit a virtual, 3-D Machu Picchu museum.