The United States military has described their efforts at cloud seeding in and around Vietnam during the 1960s and 70s as an alternative to bombing — a way to muddy up supply lines with rain instead of dropping deadly explosives. In reality, though, military airplanes still dumped tons of bombs in Southeast Asia in the Vietnam War era. In fact, the U.S. covertly dropped hundreds of millions of bombs over Laos alone, more than were used in Europe during World War II. And in the wake of this conflict, which came to be called the “Secret War,” this small Asian nation gained the morbid distinction of being the most-bombed country per capita in world history. It still holds that record. Many bombs exploded on impact, but others that didn’t have since been incorporated in unexpected ways into regional built environments, reused by locals to make homes, vehicles and more.

A lot of the devices that got dropped were “cluster bombs” — basically, these consist of hollow metal shells that open up on their way down and deploy hundreds of smaller explosive “bomblets” (which are about the size of a tennis ball). And the U.S. flew over five hundred thousand missions into Laos to drop these and other types of explosives. But they had a high failure rate — as many as a third of those bomblets didn’t detonate on impact, leaving the country littered with close to a 100,000,000 unexploded devices. And when the bombing finally ended in 1973, Laotians were left to deal with the aftermath. So they began clearing up the landscape, but they also started collecting the shells and scraps they found and putting them to use in other ways.

As it turned out, those big hollow metal cluster shells could be useful, at least ones that remained relatively intact. They have been turned into canoes, lined up to form the walls of buildings, arrayed as stilts to lift up houses and cut open to make planters. Even the smaller pieces can be melted down to make jewelry, silverware, cowbells and other things. Over time, finding and recycling these shells and scraps has grown into a national industry. And around the Laotian countryside, visitors can see tons of bombshells baked into the built environment.

It sounds at first like it could be an uplifting “swords to ploughshares” story, but it’s horrifying that survivors on the ground have had to figure out how to deal with these deadly leftover devices. Aside from those who died when the bombs first fell, tens of thousands of people have perished due to detonations in the decades since. Even now, hundreds of people are injured or killed each year from explosions — sometimes while attempting to gather up bomb metal for reuse.

Non-profit organizations working the problem estimate cleanup could still take up to a century. And this legacy is part of why over 100 nations have joined the Convention on Cluster Munitions — essentially, an agreement not to make or use or transfer cluster bombs.

The U.S., however, has not signed on, and still has a lot of cluster bombs — in recent decades, the military dropped tons of them over Iraq (in the 1990s and early 2000s). These days, a lot of the American arsenal is stored abroad. According to a recent New York Times article, the Pentagon has over a million cluster munitions stockpiled in South Korea, which are packed with close to a hundred million bomblets.