In the museum, photos of many victims who had survived the massacre hang from the walls. Photos without lights signal that the person has died.

"You can feel anger over shining lives extinguished, as the victims still have not received the apology they deserve from the perpetrators," Wang said.

She said the museum also provided written records, sculptures and a movie to help tourists understand. "The narrative of events and the ways people suffered were clearly told, and it brought us to self-examination," she said.

"History is not dead; it is alive. The flowing memory needs to be recorded. But sightseeing is too weak. It would be great if activities that younger people like－such as stage performances, room escapes and role-playing－could be added so that we can feel the history more deeply."

More sites are using digital tools to impress tourists with immersive experiences. At the "Red Building"－once the main campus of Peking University, the base of the New Culture Movement and a cradle of the May 4th Movement, which was a key to the early spread of Marxism in China－tourists can browse the original versions of New Youth, an important magazine that introduced Communist ideas using a touch screen.

At the Memorial of the Site of the First National Congress of the Communist Party of China in Shanghai, holographic projections are used to show how the Party's founders were evacuated by the back door of the meeting room to evade discovery.

On Red Street in Yan'an, Shaanxi province, workers dressed as postmen hand out an old-style newspaper to tourists. (Actually, it's a guidebook for touring the street.)