Scientists have discovered that treating CO2 with Bacillus subtilis bacteria and a helping of urea helps secure underground CO2 storage sites. The bacteria form a protective seal in the storage chambers, and also lower the pH of the saline solution, causing the CO2 to form calcium carbonate by reacting with the calcium in the rock. It is a stable way to store the CO2 underground, and it's great for the environment. Read more: New Scientist
The 2016 Rio Olympic medals are already showing defects including rusting and chipping.