Making common construction materials, such as concrete, steel and glass, is an energy-intensive and polluting process. Traditional processes to make brick involves heating clay at high temperatures for many days, releasing copious emissions. North Carolina-based organisation bioMason, however, is attempting to make innovative building materials using biotechnology—whereby they create bricks and masonry without heat, instead injecting sand with microorganisms to launch the process. These bacteria wrap themselves around sand particles, forming strong calcium carbonate crystals over the course of four days. The bricks are not yet available on the market, but have been used in a trial to create a five-story building—which was significantly cheaper to produce than a traditional counterpart.