Justification of this activity Whit this activity we expect to contextualize some specific mathematical contents. We are taking advantage of this beautiful story to make our work more real. This is a motivational activity that it will be developed through a cooperative project. In this particular case, our pupils will become architects and builders to the serve of Gediminas. They desire, like his leader, to build the greatest tower and city ever in their country. This city would become the present day capital of Lithuania. I hope you like and enjoy this activity.