During the Vietnam War, American war planes dropped 270 million cluster bombs on the nation of Laos, trying to cut off the supply lines to communist forces.
On Tuesday, President Obama pledged $90 million of U.S. aid over the next three years to help clean up the mess left by those tiny bombs, about 80 million of which never exploded.
That $90 million pledge is twice as much as the United States is currently contributing, according to USA Today.
WATCH: During a speech in Laos, Obama said a "spirit of reconciliation" brought him to the country.
WATCH: U.S. bombs have killed or injured 20,000 people since the end of the Vietnam War. Obama pledged to "dramatically increase" funding for bomb disposal.
Put simply, [Laos] is one of the most systematically rights abusing governments in the region.
Obama was the first sitting U.S. president to visit Laos, which has been strongly criticized by human rights groups over alleged abuses.
Obama was also set to visit the Philippines, but after President Rodrigo Duterte called him a "son of a whore," the meeting was cancelled. Duterte has a history of lashing out at political entities he suspects are trying to interfere.