The church itself calls it a phenomena. Some think it's miraculous, however I hesitate to use that term, so I prefer to think of it as a masterpiece of serendipity. It was discovered in 2009 at the church of St Mary, Our Lady of the Seven Sorrows in Kitchener-Waterloo, when they held an evening Mass for their titular feast day. Around 7:15PM on the feast of Our Lady of the Seven Sorrows, the light from the setting sun passed through a red stained glass window and cast its light on the wall in the sanctuary, As the Mass progressed the light moved slowly across the wall to the high altar until it came to rest on the pierced heart of the statue of Mary in the centre of the altar, before it dissipated entirely. It has occurred every year since then, (and most likely before then as well, though no one was there to see it) except 2013, when the weather was not permitting. Incidentally, 2013 was the year I went with my mother.
The feast day is coming a week next Monday, and the church website lists the day's events commemorating the feast, with exposition, benediction, confession, chaplets and rosaries with a Mass beginning around the time the phenomena begins. The website also explains that visiting the chuch on its feast day gives the visitor a plenary indulgence and explains the conditions- something not often seen or heard of today. I unfortunately cannot go due to work, otherwise I would take mother again, as we both wanted to see the phenomena. Last year, when it was on a Sunday, the church was packed full. The choir was excellent, and the service lovely, although, as I said, no phenomena that year. (Thank the weatherman. He said the weather would be cloudy with sunny periods. It was rainy, with rainier periods.)But the full church seemed to me to be a miracle in its own right. How it will be this year, I cannot say, but the church looks as though they are expecting a crowd.
So, if you are in the area or you can swing the time, go and see. But go early, just in case.