The Kouga Cultural Centre in Humansdorp, South Africa, was constructed using locally-available raw materials and local labour to emphasise sustainability and environmentally friendly practices. The building has a concrete frame with an 18 m diameter copper dome and traditional thatched roofs. The walls are constructed from blocks of hydraulically compressed earth mixed with cement. Local people were trained in block making and construction, so providing them with the skills to build high-quality, low-cost housing. The massive walls help to keep the building cool in the summer and warm in winter. A natural ventilation system draws fresh air into the building, eliminating the need for air-conditioning. The building has a sustainable aerobic waste water management system, which uses decomposing organic material as a filter for liquid and solid waste.