Situated in the Province of Hainaut the hydraulic lifts (ascenseurs) Nos 1 to 4 were designed and built by a London firm between 1888 and 1917. Each of the lifts comprises two tanks connected by pistons. A boat enters one of the tanks, the doors are closed and then enough water is added to the top tank to make it the heaviest and sink to the bottom. Once the tanks have changed places the doors can be opened for the boat to exit. 

To reduce the time taken to pass through these 4 lifts a bypass channel has been cut and the massive new lift at Strepy Thieu constructed. This is able to lift boats 73 metres. This lift has a visitor centre, panoramic views and opens for traffic in 2001.