Earth is our home and the only planet we know on which we can live. This planet provides us with everything we need in terms of living, heating, electricity, food and clothing. More and more people are living on this planet and ever more people utilize its natural resources and recreation areas, often excessively and without thinking about the future. Therefore conservational and sustainable treatment of our planet and its resources is the order of the day. Any measures that contribute to this effort can be submitted in this category, including projects on topics such as building materials, buildings, energy plants, and traffic routes.