TOKYO >> Hiroshima and Pearl Harbor, two symbols of World War II animosity between Japan and the United States, are now promoting peace and friendship through a sister park arrangement.

U.S. Ambassador to Japan Rahm Emanuel and Hiroshima Mayor Kazumi Matsui signed a sister park agreement on Thursday for Hiroshima’s Peace Memorial Park and the Pearl Harbor National Memorial of Hawaii.

“Nobody can go to Pearl Harbor, and nobody can go to the Hiroshima Peace Memorial and enter the front door, walk out the exit door and be the same person,” Emanuel said at the signing ceremony at the American Embassy in Tokyo.

“I think the hope here is that we inspire people from all over the United States and all over Japan to visit Hiroshima Peace Memorial and to visit Pearl Harbor so they can learn the spirit of reconciliation,” Emanuel said.

Under the sister park arrangement, the two parks will promote exchanges and share experiences in restoring historic structures and landscapes, the use of virtual reality and digital images for preservation and education, and best practices in youth education and tourism management, the embassy said.

“The sister arrangement between the two parks related to the beginning and end of the war will be a proof that mankind, despite making the mistake of waging a war, can come to senses and reconciliate and pursue peace,” Matsui said.

Japan’s attack on Pearl Harbor on Dec. 7, 1941, propelled America into World War II. The United States dropped an atomic bomb on Hiroshima on Aug. 6, 1945, killing about 140,000 people, and a second one on Nagasaki three days later, killing another 70,000. Japan surrendered on Aug. 15, ending the war and a nearly half-century of aggression across Asia.

Since the war, the two countries have built a powerful alliance.

In Hiroshima, some atomic bombing survivors raised concern about the sister park arrangement, saying it could help justify the use of nuclear weapons and should be reconsidered.

“I understand anguish and angst is an emotion but I don’t think you should be trapped by that,” Emanuel said. He said reconciliation between the United States and Japan “is the example of what I think this world desperately needs right now.”

Emanuel said Pearl Harbor is a revered place in the American psyche, while Hiroshima is an equally revered place in the Japanese psyche, “which is why you want to build a sister park agreement to learn from each other.”

The two parks became places of reconciliation when then-President Barack Obama paid tribute to atom bomb victims at the Hiroshima Peace Park as the first serving American leader to visit in May 2016, and then-Prime Minister Shinzo Abe, in return, visited Pearl Harbor in December that year.

Those were “key steps in deepening the alliance between our two nations,” Obama said in a statement congratulating Thursday’s sister park signing and calling it “another historic accomplishment.”

“By connecting our two peoples to our shared past, we can build a shared future grounded in peace and cooperation,” he said.

The sister park arrangement is the second between the U.S. and Japan, following one signed in 2016 between Gettysburg National Military Park in Pennsylvania and Gifu Sekigahara Battlefield Memorial Museum in what is now Gifu prefecture.

The Battle of Sekigahara in 1600 was an important battle in Japan’s feudal history. Gettysburg in 1863 is considered a turning point in the U.S. Civil War.