Doctor Who: 10 Times The Earth Was Invaded

Present throughout Earth's history and always forgotten, the Silence quietly shaped humanity - having had already invaded the planet for millennia. Standing silently in the background of history and whispering suggestions, manipulating events and affecting outcomes, the Silence were a mysterious and feared race. A religious order created by the Papal Mainframe, the Silence possessed the ability to make everyone forget their existence when they looked away.

Having existed on Earth for some time, the Doctor finally met these creatures in America in 1969. There it was revealed that they were responsible for the events of the Apollo moon landing. Needing a spacesuit to house the young Melody Pond, the Silence had suggested humanity go to the moon for the single purpose of having one at their disposal.

Now aware that history was being shaped by these aliens, the Doctor, the Ponds and River Song sought to free humanity from their hidden invaders. After three months of investigating the Silence, the team had gathered enough information to overthrow them. Recording a Silent's warning to "kill them all on sight", the Doctor hacked the Apollo broadcast and inserted this message - telling humanity to arm themselves against the invaders.

Realising they were outnumbered, the Silence fled Earth and allowed it to progress on its own.