Social media sites lit up Monday with photos taken by Chicago area residents of Monday's sundog.
Here is an explanation of the sundog from the National Weather Service:
"Another solar phenomenon is the sundog or mock sun. It [is] also produced by refraction of light through ice crystals. When the sun is near the horizon, a sundog would appear as brightly colored spots on either side of the sun."
Check out some of the photos taken in the Chicago area and posted by Twitter users Monday above. Got your own photos? Share them on the Naperville Patch Facebook page.