Martian landscape and microbial extremophiles, illustration. Microbes and other microscopic life have been found in extreme conditions on Earth, from the ocean floor to deep in the Earth's crust. This illustration shows micro-organisms in underground tunnels and fissures (lower frame) on Mars. Water ice is shown at centre right, below the surface. This artwork is based on extremophiles found on Earth, such as a range of eukaryotic organisms such as protozoa, fungi, nematodes, platyhelminths, rotifers, annelid worms and arthropods found in biofilms deep in mines in South Africa.