The Chinese Communist Party has long sought to suppress ideas that could undermine the sweeping authority it has over its 1.4 billion citizens — and the state can go to extreme lengths to maintain its grip.

In just the past few years, the government has attempted to muzzle critics by making them disappear without a trace, ordering people to physically barge into their houses, or locking up those close to critics as a kind of blackmail.

Even leaving China isn't always enough. The state has continued to clamp down on dissent by harassing and threatening family members who remain in the country.

Scroll down to see what China can do to people who criticize it.