Okay, little one. So, a long time ago in China, there was something called the Mudan Incident. This was a very sad and scary event that happened during World War II.
You see, Japan and China were fighting each other, and the Japanese army was very mean to the Chinese people. They would hurt them and even kill them.
In the Mudan area of China, there were lots of Chinese people who were trying to hide from the Japanese soldiers. But unfortunately, the soldiers found them and did terrible things to them.
The Japanese army attacked and killed over 30,000 innocent Chinese people in the Mudan area. This was a terrible tragedy and a very dark time in Chinese history.
After the war, people remembered the Mudan Incident as a reminder of the terrible things that can happen during war. It reminds us that we must work hard to create peace and love between people of all countries and all backgrounds.