Doctor Who: 10 Big Revelations We Learned In Dark Water

2. The Cybermen Have Been Living Under London The Whole Time

Dark Water owes a lot to the 1968 classic Patrick Troughton story The Invasion. This eight-part story saw the Cybermen working with the villainous human entrepreneur Vaughan and rising from the sewers to invade Earth. They didn't attack in space ships. They attacked from within the Earth. In Dark Water Cybermen marched down the steps outside St Paul's Cathedral for the second time, rising out of the Earth to enslave humanity. Up to the climatic ending of Dark Water we assumed the W3 Institute, like the Nethersphere / Promised Land was a distant world. But instead we learned that these tombs were underneath the streets of London. Doctor Chang also alluded to other institutes across the world, suggesting the Cybermen are everywhere. Though until next week, the full global impact of this invasion remains to be seen. The stakes are certainly high going into the series eight's finale Death In Heaven.