This combination photo shows an event at the University of East Asia, the predecessor to the University of Macao, on Oct. 8, 1995 (top, photo by Wong Pun Keung) and visitors taking a walk inside the campus of the University of Macao in Macao, south China on Nov. 9, 2019 (bottom, photo by Cheong Kam Ka). On Dec. 20, Macao will celebrate the 20th anniversary of its return to motherland. Over the past two decades, the special administrative region has made great strides in economic development and achieved prosperity and stability under the "one country, two systems" principle. Since Dec. 20, 1999, the historic day for Macao, what has changed? And what remains unchanged? Our selection of photos present comparative illustrations of the south China city's past and present. (Xinhua)