When you look at the moon in Der Riese it is infront of the sun which means that there is a solar eclispe on that day, Der Riese takes place in 1945, in 1945 there was a few solar eclipses.
When you do the 1st step of the easter egg in Shangri-La you can see there is a solar eclispe. And this could show us the date of Shangri-La's eclispe takes place as the same time as Der Riese (which would make the character in two places at once).
If this is true, it would suggest that Shangri-La is on Earth and takes place in 1945 when the eclipse is active.
So yeh I was pritty happy when I found this but I did not 100% find this out my self this thread got me thinking on the idea, you can see it here:
January 14, 1945 - There was an annular solar eclispe - An annular solar eclispe causes the Sun to have a ring like effect around the moon - Like the ones in Der Riese and Shangri-La. - This eclispe could been seen from many places. - So it has potential to be the correct one.
July 9, 1945 - There was an solar eclispe - It could be seen from North America, across Greenland and into Scandinavia, western Russia, and central Asia. - However Der Riese is not in one of these loacations so it is most likly not this one.
So I am gunna say that it is the eclispe of January 14, 1945 which is the corect one as the one on July 9th does not cover Germany (were Der Riese is).
This would also explain why Der Riese's clock repeats the time as the eclipse passes very quickly so if you were stuck in time it would not move. A video of this can be seen here - http://www.timeanddate.com/eclipse/solar/1945-july-9
The eclipse could be seen in these places:
Much of Asia
Parts of Africa
Parts of North America
So like I said it covers Eurpoe which would also be Germany. But this means Shangri-La is in one of these places but I am gunna say it is in Asia due to the fact Shangri-La has been said to be in china.
So if this is right Shangri-La's eclipse takes place on January 14, 1945 and it is in China or one of the other places listed.
I'm starting to think this part is not 100% true as if you look at the moons in both maps (I'll try and get images later) they are is slightly diffrent possitions as Der Riese's looks directly over the sun and Shangri-La's is not fully over the sun but almost is, which would mean Shangri-La is only slighty behinde Der Riese time wise but they would still be the same date.