Bricks, sticks, and hay are decidedly pedestrian building materials in comparison to a new building that just opened to the public last Thursday in Hamburg, Germany. Ambitious architects have built an apartment covered in a thin layer of living, breathing algae.

The building, known as BIQ (for Bio Intelligent Quotient), meets the extremely stringent passive-house standards of energy efficiency set by the International Passive House Association in part by covering the facade with 200 square meters of algae-filled bioreactors. The bioreactors act as a giant algae farm; they insulate against temperature extremes while generating populations of algae that will ultimately be fermented and turned into electricity for the building. Green architecture just got greener.

Check out more green buildings here.