NANJING, July 3 (Xinhua) -- A week-long international summer camp to commemorate humanitarians in Nanjing Massacre is being held by the Memorial Hall for the Victims in Nanjing Massacre in Nanjing, capital of east China's Jiangsu Province.

The Purple Grass International Peace Summer Camp has attracted descendants of John Rabe, John Magee and Richard Freeman Brady to participate in a series of memorial activities being held from Monday to Saturday.

According to the organizer, the three were representatives of international humanitarians who voluntarily assisted Chinese in the massacre in different ways, either by establishing Nanjing Safety Zone, filming the Japanese atrocity or treating the refugees.

Chris Reinhardt, great grandson of John Rabe, a German businessman who helped protect Chinese citizens during the massacre, attended the summer camp with his 16-year-old daughter Angelina Reinhardt to know more about their forefather.

"After visiting the exhibition hall, I am sure of the fact that 250,000 lives were saved because of Rabe's feat. It is more real," Reinhardt said.

Zhang Jianjun, curator of the memorial hall, said the summer camp was held to "commemorate international friendship and plant seeds of peace in every person's heart."

In December 1937, Japanese invaders captured Nanjing, then China's capital, and slew about 300,000 Chinese during a six-week massacre.