China has developed very sophisticated technology for intercepting and censoring Internet content. The government blocks many topics it considers sensitive or controversial and often punishes those who try to get around those bans. Reporters Without Borders refers to China as the "world's biggest prison for cyber-dissidents."
Click through this interactive to learn more about who is involved in Internet censorship, how it works and what people do to get around it.
Sources: Reporters Without Borders, The OpenNet Initiative, China Internet Network Information Center