The mist/fog was causing sunlight bouncing off the windows of this building to diffuse, giving this effect. If the observer stands at a particular angle, he will observe the beams of light hitting the ground in concentrated "window-sized" spotlights.
While the light makes the image, the proportions of the building-windows-bushes compared to the man makes it monumentally powerful. And that he is carrying the "load" adds to the symbolism of the scene... Really interesting image!
Really interesting image!