The considerations necessary to develop a feasible project week for children aged 9-13 led to three major thematic areas: subject collaboration, project methodology, and extracurricular learning locations. Before providing practical guidance for the project week, which will focus on the four elements of fire, water, air, and earth, the theoretical foundations of the underlying principles will first be explained. The starting point is subject collaboration, which encompasses all forms of interdisciplinary learning. Numerous applicable examples are vividly illustrated. Consequently, we arrive at the project week according to Karl Frey, which allows for a differentiated elaboration. Exemplary examples are also presented here. With the foundational knowledge of subject collaboration and project methodology, we reach a place of...