“The leftover casings, generally made of high-quality brass or steel, are then put to a multitude of good uses. Locals say some of the smaller bombs make good garden borders while the larger ones are pressed into service as fence posts. In fact there is so much UXO (unexploded ordnance) lying around, that whole houses have been constructed out of it.”
In operation “Rolling Thunder”, a frequently interrupted campaign which lasted from 24 February 1965 all the way through to October 1968, the US attempted to blast the Ho-Chi-Minh-trail in present-day Laos, a vital supply line used by the Vietcong.
In the Vietnam war, Laos “had more high explosives dropped on it than the total amount rained down on Germany during World War Two”.
Read more about this, and about tourism to Laos.