This month, many countries the world over will be helping spread awareness of Multiple Sclerosis—but what exactly is the disease? This video, by ASAP Science, helps explain.

Sadly, MS—an inflammatory disease where the fatty myelin sheaths around the axons of the brain and spinal cord are damaged—is currently untreatable. We don't even know its true cause. But that could change with enough research, and that's why knowing about the condition is so important. [ASAP Science]