The Flemish Community is celebrating today. These ladies were on their way to the cultural center to participate in a singing ceremony to mark the event.
I am adding a paragraph here because after reading your comments, it became clear that I should have given more info on the subject:
I must prepare a more detailed posting, one of these days, on all these festivities, holidays and celebrations.
The national Belgian holiday is celebrated on July 21.
The Flemish (Northern part of Belgium, Dutch speakers) have their own celebration on July 11 and the Walloon (Southern part of Belgium, French speaking) holiday is celebrated on September 27.
And..... Brussels has its celebration on May 8....