Discovering Mars: Exploration, Habitability and other Revelations, part 2 of 2

Mars has an underground lake beneath the polar cap. And the Curiosity rover has discovered complex organic molecules on Mars. Organic molecules are considered the building blocks of life. Another sensational discovery on Mars is the methane gas that has been detected in the Martian atmosphere. The source of methane could be either geological or most excitingly, biological. SpaceX is planning to send the first crewed spaceships to Mars as soon as in 2024.