In the CIRCU-CITY summer camp, a group of international students from different disciplines (e.g., environmental technology, energy, industrial/civil/environmental engineering, architecture and urban planning, chemistry, materials Sciences) is trained and challenged to co-develop novel Solutions for sustainable circular cities. Special attention is given to sustainable water management, climate adaptation and resource recovery as well the important role of raw materials in the transition to green mobility, renewable energy and a digital society. The summer camp makes students aware of the need for (critical) metals and mineral raw materials in the development towards sustainable circular cities. It gives our future generations thorough insights in the impact that scarcity of raw materials and policy decisions related to the management of (critical) raw materials may have on sustainable urban development, and stimulate them to find Creative alternative Solutions to still reach sustainable development goals while being challenged by unforeseen events and policy decisions. The students learn to assess the sustainability of different management choices, design options and technologies that may be used in sustainable urban development. Furthermore, they develop an understanding of business opportunities in the circular economy. The summer camp consists of a series of lectures given by international experts from several disciplines, a field visit, a board game, and a 2-days tournament. The lectures are given by experts in sustainable development, urban planning and urban adaptation to climate change, business development, sustainable mobility and integrated water management, renewable energy, life cycle analysis, water reuse and resource recovery from solid and liquid waste streams. The field trip will showcase a range of good practices in the circular economy, in particular the renewable energy and sustainable (e-)mobility transition, and the recovery of resources from wastes. In the board game "In the loop", each team of players is acting as a product-producing company, gathering raw materials to make their products. As in the real world, the future is unknown and a limited number of materials are available, so players should invest in strategies to address unexpected challenges. In the subsequent 2-days tournament, multidisciplinary student groups are challenged to design a new city district, meanwhile dealing with sustainable development goals, scenario's and challenges imposed by the tournament Board, in which the non-academic sector is also represented. They should visualize their design using Lego building bricks and other materials on a large map, and calculate the raw materials inputs needed to develop and maintain the city district they have designed.