A wooden tower in a wood

In the Sauvabelin Wood in Lausanne there's a beautiful tower - the Tour de Sauvabelin. It's made of wood, it's 35 meters tall and there's a viewing platform at 30 m. A big spiral staircase winds its way to the platform, and the entire structure is just like one of those spiral things that spins in the wind - the ones made out of many slats of wood connected with a central axle. Apparently on a clear day you can see Mt Blanc from the top!