A visitor studies photographs of Allied prisoners of war on Tuesday at an exhibition titled Forgotten Camp about the Shenyang World War II Allied POW Camp, known back then as Mukden. The traveling exhibit is on display through Dec 5 in San Francisco, the first stop in North America. ZHANG YUAN/CHINA DAILY

The exhibition also depicts the friendships that took root between the prisoners and the local Chinese workers who risked their lives to help them. There are photos showing some POW veterans returned to Shenyang years later to reconnect with their old Chinese friends who used to smuggle them food and medicine.

This is the second time the exhibition has traveled overseas, following a visit to Liverpool, England, in 2015. The show was sponsored by the Chinese Consulate General in San Francisco, China Daily and the Site Museum of Shenyang POW Camp of WWII Allied Forces.

The exhibition is important, as it offers firsthand accounts of the suffering and memories of the POWs, Florence Fong, co-founder and honorary curator of the WWII Pacific War Memorial Hall, said at the ceremony.

"If we don't learn from the past, we can't plan the future successfully," Fong said.

Jackie Huss Hallerberg, daughter of Walter Huss, who spent nine months in the Mukden camp until he was liberated in August 1945, said the exhibition made her teary. She said she doesn't remember how many times her father told her about his survivor's guilt.

"That trauma can be passed on through many generations. It's important to keep it in mind when we move forward," she said.