In 1941, Japanese fighter planes bombed Pearl Harbour in Hawaii in a surprise attack that killed more than 2,500 people.
Seventy-seven years later, Japan's Prime Minister Shinzo Abe paid tribute to those whose lives were lost.
"President Obama, the people of the United States of America, and the people around the world, as the prime minister of Japan, I offer my sincere and everlasting condolences to the souls of those who lost their lives here as well as to the spirits of all the brave men and women whose lives were taken by a war that commenced in this very place."
The event has never been officially acknowledged by a Japanese leader, and the significance was not lost on US President Barack Obama.
"Thank you for your gracious words, thank you for your presence here today, a historic gesture that speaks to the power of reconciliation and the alliance between the American and Japanese peoples. A reminder that even the deepest wounds of war can give way to friendship and lasting peace."
US Navy veterans who experienced the attack were among the attendees at the Honolulu event to mark the historic occasion.
"I think this is a great honour and I'm proud to be here."
"I'm very overwhelmed and very excited to be here and I just can't believe it."
Others were scathing of the move, looking at past atrocities committed closer to home.
Takakage Fujita is president of the Association for Inheriting and Carrying forward Murayama Danwa, an acknowlegement of Japan's wartime aggression in Asia.
"China, South Korea, Malaysia and other Asian countries suffered the worst from Japan's invasion during the war. The key is whether Abe will go to these places and wholeheartedly mourn and apologise, instead of thinking that going to Pearl Harbor is enough. Abe's view of history is twisted and dangerous. I am very critical about him bowing his head to the US, but not willing to do the same to Asia."
Aiko Utsumi, a professor of humanities at Keisen University, says Mr Abe is picking favourites by prioritising Japan's US alliance.
He says bowing to America is a snub to powerful regional neighbours such as China.
"He was thinking of the relations between Japan and the US. This time I did not detect any intention from Prime Minister Abe to pay visits and apologise for Japan's aggression in Asia, especially in China."
It is not known whether the Japanese Prime Minister is planning more conciliatory visits to other countries, or if he will acknowledge other victims of war.
Today, the Japanese leader focused on the future.
"The horrors of war have not been eradicated from the surface of the world. There is no end to the spiral where hatred creates hatred. The world needs the spirit of tolerance and the power of reconciliation now, and especially now."
