A first-day cover with commemorative stamps marking Friedrich Engels' 200th birth anniversary is displayed in Beijing, capital of China, Nov. 28, 2020. The launch event of a set of 2 commemorative stamps marking Friedrich Engels' 200th birth anniversary was held here on Saturday. (Xinhua/Lu Peng)

A girl shows a set of commemorative stamps marking Friedrich Engels' 200th birth anniversary in Beijing, capital of China, Nov. 28, 2020. The launch event of a set of 2 commemorative stamps marking Friedrich Engels' 200th birth anniversary was held here on Saturday. (Xinhua/Lu Peng)

Customers buy stamps after the launch event for commemorative stamps marking Friedrich Engels' 200th birth anniversary in Beijing, capital of China, Nov. 28, 2020. The launch event of a set of 2 commemorative stamps marking Friedrich Engels' 200th birth anniversary was held here on Saturday. (Xinhua/Lu Peng)

Wu Weishan (L), curator of the National Art Museum of China and designer of the commemorative stamps, is presented with a sheet of stamps marking Friedrich Engels' 200th birth anniversary with No. 20201128 in Beijing, capital of China, Nov. 28, 2020. The launch event of a set of 2 commemorative stamps marking Friedrich Engels' 200th birth anniversary was held here on Saturday. (Xinhua/Lu Peng)

Guests attend the launch event for commemorative stamps marking Friedrich Engels' 200th birth anniversary in Beijing, capital of China, Nov. 28, 2020. The launch event of a set of 2 commemorative stamps marking Friedrich Engels' 200th birth anniversary was held here on Saturday. (Xinhua/Lu Peng)