Need YOUR help identifying this picture - which volume no. XX does this picture appeared in?

[Monika Luisa]

Dear community,

for a current project I need to identify one particular picture from an issue of the National Geographic magazine. This picture should have appeared sometime between the 1970s and 2000s. I have already trawl through the archive - without any luck. Maybe you are familiar with this picture? I've uploaded this picture on Imgur: 

https://imgur.com/gallery/763Yqz2

If you know anything, please comment below. Thank you very much in advance!

Best,

Mengyue 

[Anthony J. Chesser]

December 1987. It says it on the bottom of the page

[Monika Luisa]

Either I've overlooked something, but I already searched every page from this issue and unfortunately could not find anything.. 

[Monika Luisa]

So that's the reason why I'm posting this. Maybe there is hope :) 

[George Thomas Wilson]

You could try March 1978.  It has an article, "The Change in Spain".  Part of that title can be seen on the page opposite the one Anthony cited. It looks like it's part of the reverse of the same, fold-out page as the photo is on, but it might be another false lead.

[Monika Luisa]

I've already looked it up, but no luck 

[Anthony J. Chesser]

I have looked through my 1972 issues and unfortunately its not in there so one year down 9 more to go.

[Monika Luisa]

Thanks for your help!