If Martian life still exists, it wouldn't survive very easily on the surface. But just under the surface there may be "survival shelters" - pools of subsurface water or hot springs that might still exist. This image shows a hot springs oasis in the distant past on Mars, when there was still an abundant atmosphere and volcanic activity. Even though the surface changed dramatically over billions of years, such an oasis may have continued to support life. It might only be organisms similiar to blue-green algae. But ancient survivors might have hung on since the warm, wet Mars disappeared. Perhaps Mars Odyssey will detect hot springs and later rovers could perform in-situ science investigations. Astrobiologists are hoping to make such a discovery because a hot springs on Mars might be the best place to find life.