Ron Nirenberg, chair of Sister Cities International (SCI), views photos during a photo exhibition with the theme of "Trans-Pacific Exchange and Cooperation -- Shanghai Commemorates the 40th Anniversary of China-U.S. Diplomatic Relations" in Houston, Texas, the United States, on July 17, 2019. An exhibition of more than 300 photos featuring cultural exchanges, economic cooperation and friendship between China and the United States opened here on Wednesday. (Xinhua/Liu Liwei)