The processes that build mountains and wash them to the sea, that clean up pollution and that create oyster shells are all driven by molecular scale reactions. We use nanotechniques to “see” how fluids, such as water, oil and CO2, react with natural solids. We learn the secrets of nature and apply the new knowledge to solve some of society’s challenges, such as cleaner water, safer waste storage, converting CO2 to solids that are stable for geological time, squeezing more oil from depleted reservoirs and designing biomimetic materials.