If you look through the pictures, you can find:
-men carrying large stones, and throwing them into the wall panels
-men mixing concrete in large flat metal pans
-men carrying buckets of concrete, and dumping them into the wall panels
-men standing at the edge of the pit where the walls are being constructed, supervising
-wall panels (into which the concrete is poured and stones are thrown) about up to ground level
-men standing around, doing nothing at all (I have no idea what was holding up the work in those later pictures)
Maybe I have these pictures in backwards order, and the men were just gathering waiting for the work to begin. Could be . . . I wasn't actually there . . .