Colonies of microorganisms living in the north and south poles of the Earth, living in such difficult circumstances that might survive on Mars.
Colonies of bacteria were found on the rocks near the poles. These places are really not very suitable for life — a combination of extremely low temperatures, strong winds and extreme ultraviolet radiation (as is known, the main ozone holes are located just above the poles) look intimidating. Therefore, only less than a half percent of the polar areas inhabited at least some vegetation. But 95 percent of the surveyed scientists stony plains inhabited by micro-organisms!
It has long been known that colonies of micro-organisms living in the hot deserts under transparent stones that let in the light. But to discover life beneath opaque blocks of basalt and granite was not expecting anyone. It was found that these organisms lack the light that falls under rocks through the cracks between them, being reflected from the surfaces of the adjacent stones.
Also, due to changes in temperature (hot stones sun and cool down when it is not) occur progress in stone placers, some stones are in the dark, while others fall into the light. After such progress microorganisms "migrate" to the dark stone at the lighted.
Find life in such difficult circumstances has once again revived the hopes of the scientists on the existence of life on other planets. If life — so stubborn thing, maybe we really are not alone in the universe?