As scientists breach the invisible barrier of outer space with a new discovery every day, an unsettling mystery continues to shroud the Red Planet.

The growing popularity of Mars perhaps stems from the fact that it is considered the only other habitable planet after Earth.

Over the years, scientists have mounted several missions to Mars, but only 22 have been successful out the 55 launched.

However, the greatest mystery that continues to baffle scientists are the unexplained signals that point towards signs of life on the planet, but no conclusive evidence of this has been found.