Cyanobacteria are life-sustaining micro-organisms that have played a key role in providing oxygen to our planet’s oceans and atmosphere, thus allowing life to flourish on Earth. It was believed that they can only survive in habitats with enough sunlight, water, and nutrients. But scientists were baffled when they found these organisms living 2,000 feet beneath the earth. This impressive discovery may have important implications in our quest to find alien life on Mars.