In the Wilhelmsburg district of Hamburg, visitors can see what living will be like in the future. In 2013, the first apartment building using a bioreactor facade was completed there. Two sides of the building have glass walls inside of which microalgae are offered ideal living conditions. Sunlight and carbon dioxide transform the algae into biomass and heat. As a result, the living facade is a heating source for the whole building. The algae building, which is ascribed a Bio Intelligence Quotient (BIQ), is an example of how sustainable residential construction can benefit cities in the future.