In case you forgot your history lessons, the US dropped atomic bombs on Hiroshima and Nagasaki to end World War II in August 1945.
The bomb caused an unthinkable amount of damage in the cities, killing tens of thousands of civilians in a horrifying wave of destruction.
People and governments have debated the use of nuclear weapons ever since, having seen the horrors the weapons can cause. The ethics of America's decision to drop these bombs continues to be argued.
Ben Rhodes, assistant to the president and deputy national security advisor for strategic communications and speechwriting, wrote in a post on Medium Obama is going to use the visit to honor the innocent people lost in the war and "pursue the peace and security of a world without nuclear weapons."
The visit will also recognize the repaired relationships Japan has with the United States.
So, on May 27, the President will visit the Hiroshima Peace Memorial Park, a site at the center of the city dedicated to the victims of the atomic bombing, where he will share his reflections on the significance of the site and the events that occurred there. He will not revisit the decision to use the atomic bomb at the end of World War II. Instead, he will offer a forward-looking vision focused on our shared future.
On the same trip, Obama will be visiting Vietnam, another place where the United States' debatable military actions caused a lot of destruction.
Naturally, Twitter took the announcement of Obama's visit as an excuse to freak out. People accused Obama of making an apology tour and expressed their distaste, despite the fact the White House said Obama will not be making an apology.
Because, you know, it's just disgusting the leader of the United States might want to honor civilians the United States killed in one of the worst human atrocities in history.
And of course, Twitter is the best possible place to have meaningful discussions on serious and nuanced subjects.
Here's what people said.
Citations: Obama to Be First Sitting President to Visit Hiroshima (The New York Times), Hiroshima (The New Yorker), The First Sitting U.S. President to Visit Hiroshima (Medium), Barack Obama to visit Hiroshima on Asia trip (BBC)