Battle of Canary Wharf

The Battle of Canary Wharf was one of the major battles between Humans and aliens in Earth history.

Origins
The Battle of Canary Wharf had its roots in the escape of the Cult of Skaro and the Genesis Ark into the Void from the Last Great Time War. This caused a crack in the universe, allowing travel between dimensions more easily than should have been the case after the demise of the Time Lords. (DW: Doomsday)

Beginnings
From the crack in the universe, the Parallel Earth Cybermen were able to travel from their dimension into ours, and infiltrated the planet in the disguise as the benign ghosts of deceased Humans. (DW: Army of Ghosts)

After two months (three years in Parallel Earth time), the Cybermen suddenly appeared in their true form,occupying every landmass on the planet before breaking into houses and promising to upgrade all Humans, commanded by the new Cyber-Leader. (DW: Army of Ghosts/Doomsday, TW: Everything Changes)

Simultaneously, the Cult of Skaro had exited the Void Ship with the Genesis Ark. The Cult, led by Dalek Sec, extracted information from a member of staff from Torchwood 1, and proceeded to communicate with the Cybermen via Dalek Thay and declare war (or in Dalek Sec's words, "pest control"). (DW: Doomsday)

The Battle
After a skirmish (Humans versus Cybermen versus Daleks), the Cult travelled to the main room in Torchwood Tower (Canary Wharf), elevated outside above the roof, and opened the Genesis Ark, releasing millions of Daleks who, under Sec's command, proceeded to "exterminate all life-forms below", killing Human and Cyberman alike. (DW: Doomsday)

During the battle, the Cybermen began to convert Torchwood personnel, like Yvonne Hartman and Lisa Hallett in large numbers. (DW: Doomsday, TW: Cyberwoman) These were, at least in some cases, not full conversions, with the brain removed and put in a Cyber-shell, but partial conversions where the Cybermen built over the Human body beneath. (TW: Cyberwoman)

The Doctor and Rose Tyler opened the Void, sucking all the Daleks and Cybermen who had been in the Void back into it, and finally sucking Rose herself into the parallel Earth where her parents, Jackie Tyler, that universe's version of her father, Pete, and Mickey Smith had decided to stay. The entire battle had lasted less than a day, but the Doctor commented that "so many" people died that day, and that the effects on Earth were devastating. (DW: Doomsday)

Aftermath
Afterwards, of Torchwood 1 823's personnel, there were only 27 known survivors. 467 were dead, with the rest numbered missing. Humans converted into Cybermen using only materials from the main universe remained, unaffected by the Void and were interrogated and studied by the remaining Torchwood Institute personnel. (torchwood.org.uk) Between the active Torchwood 2 and 3 branches, there are only 10 or so remaining Torchwood staff. (DW: The Sound of Drums)


 * Survivors included Lisa Hallett herself, Hallett's lover Ianto Jones and Dr. James Tanaki.

The governments of the Earth denied the battle had ever happened and blamed the reports on mass hallucination caused by terrorists polluting the water supply with psychotropic drugs. (TW: Everything Changes)