As Chinese people across the world are voicing indignation over Japan's provocation in the issue of the Diaoyu Islands, Tuesday also marks another event in history-the September 18th incident.

That's when Japanese troops raided a railway station in northeastern China's city of Shenyang 81 years ago, which eventually led to the Japanese occupation of Northeast China.

In the Northeastern cities of Shenyang, Changchun and Harbin, sirens began wailing at exactly 18 minutes past nine to mark the September 18th Incident which was followed by Japan's invasion of China 81 years ago.

The 9-18 history museum in Shenyang took in tens of thousands of visitors in a single day. People have come to learn about the chapter of history from both China and Japan.

A Japanese visitor says, "Japan invaded China and caused great pain to the Chinese people, but many Japanese people aren't well-informed about this. Today we came to see the historical records. We realized the immense suffering and pain Japan had caused China. I feel we can't allow a repeat of such history."

And in the southern metropolis of Shenzhen, which borders Hong Kong, pupils from the Chinese mainland and the Hong Kong SAR spent a special day of learning at the Chinese British Street History Museum to commemorate the 9-18 incident.

A visitor says, "Today by visiting the museum, I learned about China's struggles against Japanese imperialism. I won't forget history."

Trips were also organized for Chinese soldiers to visit predecessors who fought against Japanese invaders during the second world war.

A soldier says, "As a frontier soldier, I won't forget history and I will protect the safety of China's border."

On this very day in 1931, Japanese troops raided a railway station in Shenyang and then accused the Chinese army of being behind it. The move marked the beginning of the Japanese invasion and occupation that lasted 14 years.