Tourists gather on the Great Wall outside Beijing. Reuters/Stringer China's population was approaching 1 billion when it enforced a one-child-per-family policy in the late 1970s. Exceptions were only made in the cases of ethnic minorities and rural couples, who were sometimes allowed two children.

The law is not the most popular, and there have been some unintended consequences, including a skewing of the population towards males and a disproportionate representation of elderly people.

Still, many argue that it has been important for the country, as it has helped reduce famine and limited a population that was rapidly growing.

With the policy in place for over 35 years, the current population still rests at around 1.4 billion.

These photos from Reuters are good examples of how crowded the country has become.

(Captions by Reuters and Jack Sommer)