Titan
Titan is a moon of Saturn that is larger than the planet Mercury. It is the only moon in the solar system known to have clouds and thick, planet-like atmosphere. Titan's atmospheric pressure is about 60 percent greater than the Earth's. Which is about the same pressure found at the bottom of a swimming pool. Titan's thick cloudy atmosphere is mostly nitrogen, like Earth's, but may contain much higher percentages of chemicals such as methane and ethane. The atmosphere may be so thick that it actually rains "gasoline-like" liquids.
The organic nature of some of the chemicals found in Titan's atmosphere might indicate that this fascinating moon could harbor some form of life. Here on Earth we have Extremophiles that can exist and thrive in acidic, high/low temperature conditions you might not expect as possible for any living thing. One form of these Extremophiles here on Earth can convert methane into energy. So, if we have microorganisms on Earth that can use methane as an energy source to survive could there be a living analog of that extremophile living on Titan? The evidence seems to be constantly stacking up - organic compounds we find in space, microbes surviving on the moon, and all these interesting moons and exoplanets we're discovering more about...to me it seems alien microbial life is certain and intelligent life, Alien Life, at least probable.
Space Footage - Jupiter and Saturn
** Image of Titan is from NASA, the source of the material.