HOMEWORK : What is the importance of Abe's visit in Pearl Harbor?

I'm not sure with the importance but I know that Japan's president Abe will have to apologize to US, Korea and to the world. Because the first world war happened because of Japan. So they have to apologize to the world for giving scars to many countries. And I'm very angry that Japan didn't apologize about the military sexual slavery . They have to apologize befor all the womens who has been slave's will die. They will have to apologize or else!