This is a stunning double splash page taken from the Italian comic Capitan America #21 (Captain America #105)
Too bad that, back in those days, printing technology could not print on the entire paper sheet and some part of the drawing had to be left out. I assume (but I have never seen Kirby's original pencils so I might be wrong) that originally it was a single drawing that was subsequently splitted in two pages.
Unfortunately, part of the drawing has been cut out. If you try to "recompose" the original image putting them side by side you get this (I'm switching to a modern digital reprint now)
It is clear that there is a "strip" of the original art that was deleted. What a pity!
As a fun (slow) project I decided to join the two hi-res scanned pages above, clean them, restore them and then print a big poster. I have not done it yet. I started a "warm up" project instead, starting from the two low-res digital versions you see above, so that the pages are already cleaned and I do not have to worry about faded colors, yellowed paper, dot patterns and so on.
I will show here the progresses and the way I do it as I move on. Once I am done with this I will use the result as a guide to work on the hi-res picture: the low resolution of the brand new digital comics are ok to view them on a screen but makes it impossible to print a big poster out of them.
So, where do we start? Open the left image on your Photoshop (PS from now on), enlarge the canvas to 200% to the right, add the second image as a new layer.
Try to move it (up and down too!) to a place that looks right.
To help me in the positioning of the two layers I created yet another layer to draw a few connecting lines.
If you wish you can play with the two pages yourself (page1 and page2)