A visitor takes photos of commemorative coins displayed at a major exhibition to commemorate the 40th anniversary of China's reform and opening-up at the National Museum of China in Beijing, capital of China, Nov. 24, 2018. (Xinhua/Yin Gang)

Visitors look at the model of locomotive during a major exhibition to commemorate the 40th anniversary of China's reform and opening-up at the National Museum of China in Beijing, capital of China, Nov. 24, 2018. (Xinhua/Yin Gang)

A visitor displays a customized postcard at the exhibition area of Xinhua News Agency during a major exhibition to commemorate the 40th anniversary of China's reform and opening-up at the National Museum of China in Beijing, capital of China, Nov. 24, 2018. (Xinhua/Yin Gang)

Visitors look at the commemorative coins during a major exhibition to commemorate the 40th anniversary of China's reform and opening-up at the National Museum of China in Beijing, capital of China, Nov. 24, 2018. (Xinhua/Yin Gang)

Visitors experience intelligent calligraphy writing desk during a major exhibition to commemorate the 40th anniversary of China's reform and opening-up at the National Museum of China in Beijing, capital of China, Nov. 24, 2018. (Xinhua/Yin Gang)

Spacesuit is displayed during a major exhibition to commemorate the 40th anniversary of China's reform and opening-up at the National Museum of China in Beijing, capital of China, Nov. 24, 2018. (Xinhua/Yin Gang)

A staff member shows a phone with a foldable display screen during a major exhibition to commemorate the 40th anniversary of China's reform and opening-up at the National Museum of China in Beijing, capital of China, Nov. 24, 2018. (Xinhua/Yin Gang)

Visitors experience customized postcard making at the exhibition area of Xinhua News Agency during a major exhibition to commemorate the 40th anniversary of China's reform and opening-up at the National Museum of China in Beijing, capital of China, Nov. 24, 2018. (Xinhua/Yin Gang)