It's come up on Ropes and Poles before that being able to speak Flemish is a good way to improve your pioneering. This project showed up in my Facebook feed courtesy of Ploeg Technieken and I thought I'd share it with the English speaking Scouting world.
Here's a video of the construction process, including a timelapse and details of the planning process, using models, and the construction process, which included using a small backhoe to dig foundation trenches.
This tower was built by the 92ste Aartselaar - Reet group in Belgium as part of their Annual Scoutsorama camp. It included a viewing deck on top, a climbing wall including cargo nets and plywood sections with moulded grips, and a 'slide' designed to be ridden in a sled.