Science's Greatest Mysteries - Season 1 Episode 5 -

In 1959, a Russian space probe, Luna 3, took the first ever images of the far side of the Moon, the side that until this moment had been hidden from us. The iconic images shocked the science world, revealing the far side to appear completely different from the familiar near side. Since this moment, scientists around the globe have found more puzzling and unexplained differences between the Moon’s two sides. They’ve been spending over half a century trying to understand why.