Town Hall Square has been a marketplace and the centre of this old Hanseatic town since the Middle Ages. It became the centre of the Lower Town at the turn of the 13th and 14th centuries. As a square, it plays an important role today as well. In summer it is filled with outdoor cafes, it plays host to the Old Town Days and other medieval festivals, and is also a venue for open-air concerts, fairs, and more. In winter it becomes an enchanting Christmas market, the centrepiece of which is a towering spruce tree. The tradition of celebrating Christmas festivities here dates back to 1441 when the Brotherhood of the Blackheads are thought to have erected the world's very first Christmas tree.