I took this photo while walking through Illini Grove at the University of Illinois at Urbana-Champaign (UIUC). I had gone out for an evening walk and brought my camera with me. It was shortly before sunset when passed through the park. I happened to notice how the sun was shining through the leaves of the trees as it was getting lower and lower in the sky.
Despite the clear, crisp air that evening, the sunrays showed up fairly well in the photography. Normally it helps to have some moisture in the air to help them show up. However in this case, I believe the contrast of the light and dark helps bring out the sunrays, along with a bit of moisture in the air.