In the future we may be surrounded by concrete structures, which are able to self-heal cracks in their structure, with special bacteria doing the job for us. Tiny cracks in concrete do not necessarily affect structural integrity in the short term, but they do allow water and other chemicals to seep into the structure, which may cause big problems over time. Self-healing concrete has dormant bacteria and a food source (starch) embedded in the concrete. When a crack appears in the concrete, water seeps in and reactivates the bacteria. After they awaken, the bacteria eat their packed lunch and then conveniently excrete calcite, which heals the crack. The bacteria can survive dormant in the material for 50 years. Explore self-healing concrete on the Institute of Making website: https://www.instituteofmaking.org.uk/materials-library/material/self-healing-concrete.