Beijing, December 17 (Youth.cn) - With flags of People’s Republic of China and Macao Special Administrative Region (SAR) raised at the Garden Hall of Macao Cultural Center, Macao SAR officially returned to the motherland at 0:00 am on December 20th, 1999. Over the past quarter-century, with fully support of the central government, Macao has achieved great progress in social and economic development, which is a successful demonstration of “one country, two systems” principle with Macao characteristics.