One of China's largest and most pervasive surveillance networks got its start in a small county about seven hours north of Shanghai.

In 2013, the local government in Pingyi County began installing tens of thousands of security cameras across urban and rural areas — more than 28,500 in total by 2016. Even the smallest villages had at least six security cameras installed, according to state media.

Those cameras weren't just monitored by police and automated facial recognition algorithms. Through special TV boxes installed in their homes, local residents could watch live security footage and press a button to summon police if they saw anything amiss. The security footage could also be viewed on smartphones.

In 2015 the Chinese government announced that a similar program would be rolled out across China, with a particular focus on remote and rural towns.