Using raw materials and other finite resources responsibly without exhausting them – the term “sustainability” dates as far back as to the 18th century when Saxon mining administrator and forestry expert Hans Carl von Carlowitz (1645–1714) demanded that the number of trees to be cut should not exceed the number that could grow back. Today, “sustainable development” in the areas of environment, economy and society aims to meet present-day needs without jeopardizing the ability of future generations to satisfy theirs. Attention is specifically focused on green technologies to reduce energy consumption and CO₂ emissions. How familiar are you with the concept of “sustainability?” We invite you to test your knowledge.