Liu Suzhen, one of the Nanjing Massacre survivors, passed away on Sunday at the age of 93, reducing the number of registered survivors to 35, according to the Memorial Hall of the Victims in Nanjing Massacre by Japanese Invaders on Monday.

The Nanjing Massacre took place when Japanese troops captured the then-Chinese capital on Dec. 13, 1937. Over six weeks, they killed approximately 300,000 Chinese civilians and unarmed soldiers in one of the most barbaric episodes of World War II.

During the Massacre, Japanese soldiers scalded six-year-old Liu's right arm with boiling water. "We hid in a shelter on Shanghai Road. The sound of planes bombing above was deafening. Both adults and children were too scared to go out. It was very, very tragic," she had recalled.

"We must not forget the suffering we endured in the past. We must remember them firmly," said Liu, haunted by the tragedy throughout the rest of her life.

The Chinese government has preserved the survivors' testimonies, recorded in both written and video transcripts. The documents on the massacre were listed by UNESCO in the Memory of the World Register in 2015.