Issue #21 of architectum deals with the topic sustainable building. The construction industry has a vast potential to contribute to a sustainable society. Buildings are responsible for 40% of the total EU energy consumption over their lifespan. Therefore all buildings constructed as of the beginning of 2021 have to consume nearly zero energy, according to the EU. This will affect the way we build in the future. Some of the best examples of sustainable and energy-efficient projects can be found in this issue, including an interview with Lien Vansteenkiste and Hein Verbeke from Groep III architects, Belgium.