Anneessens

Along with the seven streets that lead to it, the square was established in 1639 on the "Voldersbempt," an open piece of pasture. It was bounded by the Anderlechtstraat, the Zenne, and the Kleine Zenne. Until the covering of the Zenne, it was the site of the flea market or old market. Due to the construction of the wide avenues, which attracted a more affluent public, and complaints from the residents about rotten and flea-infested goods, the stalls of rags and various objects were moved in March 1873 to the Vossenplein in the Marollen. The Brussels residents then called the square àven à mèt (old old market).

Wikipedia