The "Agenda 21 Partnership" between Aachen and Cape Town was established in 1999 at the suggestion of the Welthaus in Aachen together with a self-help organization in Khayelitsha, a township in Cape Town. The official Memorandum of Agreement (MoA) was signed in 2017.

Another principle is 'learning at eye level'. Many projects combine social, ecological and educational issues: student and knowledge exchanges, bicycle recycling projects, greening projects, school garden projects, school partnerships and student exchanges, a total of 15 mural painting projects - and there is the Aachen/Cape Town climate ticket.
Since 2015, employees from both city administrations have been comparing municipal processes and the development of sustainability strategies. Colleagues from Aachen have already been to Cape Town twice, and in June 2018, people from Cape Town will be coming to Aachen for the second time.