Barcelona is one of the world’s pioneers in urbanism and architecture. In the Autumn of 2019, Valldaura Labs became a platform for ecological design and construction by students in the Master in Advanced Ecological Buildings and Biocities with Daria Bychkova of Bureau Chekharda from Russia.The Barcelona municipality supported the design and construction of a natural playground in the Collserola Natural Park developed by MAEBB students with professional guidelines from the Russian Architectural Bureau, Chekharda. The Colserolla Park includes many underdeveloped public spaces which also offer beautiful scenery for a raw nature playground. Valldaura Labs drew on this opportunity for professional collaboration and student experiential learning to host a design-build project conducted by students of the Master in Advanced Ecological Buildings, focused on natural compositions of fully traceable tree structures in the form of a children’s playground, located in a popular family destination point on the property.Construction of such natural playgrounds is connected to many technical difficulties. Beginning with careful tree identification, mapping and extraction from the forest through meeting safety standards and regulations written for the linear geometry playgrounds. To respond to these challenges, students of the MAEBB with direction from Daria Bychkova, used digital tools, 3D modeling software and advanced tracing techniques in the development process of the project.  Material traceability and ecologically conscious decision-making was a fundamental aspect of the project. It included deliberate and conscientious use of natural resources, celebration of connection to unaltered natural tree structures, as well as creative solutions for ecologically conscious construction. As part of the pedagogical objectives, the project also emphasized how such natural playgrounds reconnect urban citizens to nature in a controlled way and create an island of spontaneity in modern urban jungles thus stimulating creativity, interaction and growth.The project also introduces a delicate approach to playful architecture which appeals to the senses and imagination of all ages. Regular wood, stones and ropes are turned into magnificent large scale artistic objects which can become architectural landmarks.By Bureau Chekharda and Marziah Zad