Despite its magnitude, the Nanjing atrocity has often been overshadowed by other World War II events in Western historical accounts. Chang's book became a best-seller and introduced many Western readers to the tragic history for the first time.

For siblings Felicia and Joshua Guo, both attending Valley Christian High School, their involvement in park maintenance led them to discover Chang's work and motivated them to delve deeper into history.

Felicia, 16, initially viewed it as a routine volunteer activity but became inspired after learning about Chang's dedication and the challenges she faced.

"School textbooks barely scratch the surface, often dedicating just a paragraph or two to this significant historical event," Felicia said. "I looked online and then researched the history and her books. Iris Chang put everything on the line to tell this story, facing intense criticism and backlash. Her courage in pursuing truth despite opposition is truly inspiring."

The 14-year-old Joshua, introduced to Chang's story by his sister, shared similar sentiments. "Understanding her sacrifices and dedication to spreading knowledge made me want to contribute," he said. "It feels like a responsibility to honor her memory through this work."

He said what drew him to this history was its neglected nature. "While textbooks acknowledge the event, they rarely delve into the details. There must be a reason why some people try to obscure this history or fear discussing it. Understanding what actually happened becomes even more important because of this," he said.

The park cleanup program, initiated five years ago by the Silicon Valley-based Hanlin Education Foundation, has grown from just three participants to a regular group of 15 to 20 students every month.