We’ve all heard that too much mercury exposure, especially from fish, can be bad for us. But liquid mercury was used as far back as 3,500 years ago and was found in Egyptian tombs. It’s also called quicksilver, like the X-man character, because it’s fast-moving and surprisingly heavy, originally named after the wing-footed god and our fastest moving planet. It’s found in old glass thermometers and new fluorescent bulbs, so if one breaks don’t breathe in the fumes. But why is it dangerous? Mercury can be absorbed through unbroken skin, ingested or inhaled, and over time it can lead to health problems and even death.