On December 20, 1999, Macau was officially handed back to China after over 400 years of Portuguese rule. This event marked the end of colonial governance and the beginning of a new era under Chinese sovereignty, following the "one country, two systems" principle. This framework allows Macau to maintain its own legal and economic systems while being part of China. The return was part of a broader trend of decolonization in the late 20th century, with Hong Kong also returning to China in 1997. Since the handover, Macau has experienced significant economic growth, largely driven by its gaming and tourism industries, becoming one of the world's richest regions.