On September 13 European Space Agency’s (ESA) Mars Express orbiter spotted an elongated cloud on Mars near the Arsia Mons - a dormant shield volcano 12 miles high. The cloud stretches for about 930 miles (1500 kilometers) and hasn't dissolved for over a month. That's nothing extraordinary - similar clouds has been spotted on Mars in 2009, 2012 and 2015 at winter season. The giant Martian volcanoes, rising high into the atmosphere, are playing a role into creation of those kind of clouds.