IJssel has also caused many problems over the centuries, because it often overflowed its banks. Nowadays Deventer has a flood defence, but the Welle ('wal', the name of the street over the quay) is still regularly under water during high water. Dike breaches of the IJssel have created many gullies in and around the city , such as the Douwelerkolk and the Klinkenbeltskolk. In addition to the IJssel, Deventer has a large number of waters. The Schipbeek is a brook partly dug on behalf of the city that rises in Germany and flows into the IJssel near Deventer. In the past, the stream was navigable, so that wood and Bentheimer sandstone could be brought in, among other things. Another waterway that was built for shipping and which flows into the IJssel in Deventer is a branch of the Overijssels canal, through which Deventer was connected to a large system of canals through Overijssel. It was dug in the mid-19th century and opened in 1858. Culture Sights The Grote Kerkhof square (Grand Churchyard) The Saint Lebuïnuskerk (St. Lebuin's Church) in Gothic style, with ceiling paintings and an organ. Its tower can be climbed in summer. The City Hall with a façade built in 1693 in Dutch Baroque style The Brink (market square) with houses, shops, and cafes dating from 1575 to 1900. The market square is also the centre of Deventer nightlife. Alongside this square there is the Bussink "Koekhuisje", where the honey-cake Deventer Koek is been sold. Markets take place every Friday (including one on Good Friday, following a medieval tradition) and Saturday. The Waag (Weighing-house) on the edge of the Brink square, built in 1550 and restored in 2003. The Deventer City Museum is housed inside the Waag. The Museum's collections include industrial and trading history, paintings by Gerard Terborch and Han van Meegeren, silver objects, and prehistoric findings). Thea Beckman's novel Het wonder van Frieswijck ("The Frieswijck Miracle") features the Waag. On the outer wall of the Waag hung until 2016 a large kettle that is over 500 years old, said to have been used for a public execution in the late Middle Ages; a man who had produced counterfeit coins was cooked to death in it. According to local tradition, there are holes in the kettle shot by footmen of Napoleon's army around 1809. In 2017 the kettle has been placed inside the building, at the entrance