How did the land of Japan, an island nation, come to be the island nation it is today? This is a film-like reenactment of the beginning of the phenomenon. Why is it that more than 70% of Japan's land area is made up of mountains and there is very little flat land? Watching this undersea volcanic activity, we can understand the formation process and the reason for its shape. It is also a test case to see how large the land area must be for plant and animal life to begin to take root and flourish. This needs to continue to be studied with precision.