Wow! Where did you find that one Les? I’m amazed!
The place is the old Olympic stadium where the first modern Olympic games were held at the end of the 19th century. The picture could be from a display put on by the Greek forces which returned from Italy after the liberation in 1944. Alternatively it could be a propaganda event during the civil war. If you look there’s a bren carrier in the background.
I’d love to be able to take a closer look at the markings; they’d tell me more about the approximate date. Do you have the picture in higher res? Are there any more from the same event?
Fyll