Jiang Qinqin reads the last letter of Yang Kaihui, Mao Zedong's wife, who was killed in 1930 at the age of 29.[Photo provided to China Daily]

Guan also mentioned that Xia, the 16-year-old who died for the Ming court, made a moral choice to be faithful to the education he had received and the culture he had inherited.

"Reading his last letter thrilled me. It's really hard to imagine how a teenager calmly wrote down the words as he prepared for his execution," Guan added.

Other than letters from brave people, the words left behind by some others are also thought-provoking. Such cases include the last letter by Qiu Wenzhou, a Taiwan father who wrote to his daughter, who was 6-year-old, before he died of cancer.

Liu Yu, executive director of the program, said a last letter is "a solemn ceremony to say farewell".

"For family and friends, a last letter is an important legacy," Liu added.