Vintage 11 folding post cards from mexico/texas

Not quite sure what I have and was wondering if anyone can help. They are 11 town pictures back to back folding post cards. Ciudad Juarez, Mexico pics on one side and El Paso, Texas on the other. They all fold into one another and go in a thick brown paper holder that has a map on the front of the two city's. Can't find any info was wondering if anyone can help?