Territories that fall within the sovereignty of the People's Republic of China, but do not form part of mainland China. The concepts of "special administrative regions" and "one country, two systems" were established by the Chinese government to re-integrate Hong Kong and Macao into China. As SARs, Hong Kong and Macao retain their capital systems and have a high degree of autonomy. However, the mainland government remains responsible for the defence and foreign affairs of both SARs, but each SAR is authorised to engage in external affairs and participate in international organisations, if so permitted by its terms. The mini-constitution for each SAR is found within their respective basic laws.