As soon as we hear the name "Mars" we think of green Martians. But how true is the legend of this people? This is a very difficult question. In 1966 a rock from the planet Mars was found in the Antartic. His age is between 3.8 billion (age of the oldest stones on Earth) to 4.5 billion years (at that time sun and planets developed). After long research work it was possible to prove that extraterrestial life could have existed on this stone. The reason being: · The stone contains tiny carbonate balls, mineral deposits of carbon and oxygen mixed with calcium, iron and magnesium. Only about one percent of the rock contains this balls which have a diameter not larger than a human hair. On Earth carbonate deposits are created by sea organisms but carbonate can also develop without any interferance from a living creature. We have to ask ourselves now the following questions: How and why did this carbonate balls develop in this rock? Has water played a role in the development? · Modern extraction techniques proved the existence of "PAH" (polycyclic aromatic hydrocarbonates) in the balls - a material which is often produced by decaying organisms. The PAH was irregularly distributed in the balls. This could prove that small organisms are responsible for the accumulations. But we have to ask ourselves as well whether these carbonate balls really come from Mars or whether they assembled in the stone only when it was already on Earth. It was tried to determine the age of the balls. The first test resulted in the expected age of approximately 4.5 billion years. According to today's knowledge there could have been life on Mars at that time! But a further measurement stated that the balls had an age of 1.4 billion years only! So, what to believe now? The first figure is more reasonable - but that does not mean that it is true. Could biological life have existed on Mars? NASA pictures of the surface of Mars show some soil structures which remind us of river beds on Earth. Can we deduce from this that there has been flowing water at a time? Nobody can confirm such an assumption at this stage of research - but it cannot be denied either. As said before the carbonate balls could originate from living creatures. And the formation of an atmosphere as on Earth is not a coincidence. Therefore this process could repeat itself at any time somewhere in the All - perhaps it has already. We will not know for quite some time!