Oh it has nothing to do with Bolivia, it is a type of ending in story telling, here is a copy pasted explanation from Tv tropes.com
" A Bolivian Army Ending is an Ending Trope that occurs when the main characters face seemingly insurmountable odds which, for once, the main characters actually seem unable to surmount.
This trope usually leaves out the actual demise of the protagonists, ending just as they face the fire. Thus, while previous circumstances and/or antagonists indicate their unseen yet inevitable destruction, the actual fate(s) of the hero(es) hide(s) behind the horizon evermore, unless the fiction continues this/these character(s) in an upcoming/additional body of work.
The trope is named for Butch Cassidy and the Sundance Kid. For both the end of the movie, and their real life ending."