Cardiff

Cardiff was the capital and largest city of Wales. A spacetime rift is located near Roald Dahl Plass and Torchwood 3 were located there, both near the Plass.

Founding of the city
In 27 CE, the city of Cardiff was founded. Jack Harkness, the leader of Torchwood 3, had travelled back to that time period on the insistence of his brother Gray. Gray and his unwilling accomplice John Hart, buried him. The immortal Jack would remain underground until 1901. (TW: Exit Wounds)

19th century
The Doctor and Rose Tyler encountered Charles Dickens and the Gelth on here on Christmas Day 1869. (DW: The Unquiet Dead) Torchwood Cardiff, a branch of the Torchwood Institute later called Torchwood 3, was established here. (TW: Fragments)

20th century
Torchwood Cardiff continued to exist. During World War II, refugees from the Blitz in London were moved here. (TW: Ghost Machine)

2000s
"Margaret Blaine" was elected as Lord Mayor of Cardiff following her escape from the destruction of 10 Downing Street. She planned to demolish Cardiff Castle and to construct the Blaidd Drwg (English: Bad Wolf) nuclear power station. She planned on using a tribophysical waveform macrokinetic extrapolator as a pan-dimensional surfboard to escape the solar system after Earth's destruction. (DW: Boom Town)

Circa September 2006, the Doctor, Rose and Jack Harkness, travelled to Cardiff to refuel the Doctor's TARDIS and to meet up with Mickey, the group discovered this plot. The rift partially opened, causing a small earthquke (DW: Boom Town)

By this time, humans living in Cardiff had started to notice and take advantage of the alien presence on their world. Illicit merchants for alien artefacts traded in the town and profited off of them such as the "Ghost Machine", which had fallen through the Rift (TW: Ghost Machine). An underground "fight club" where the alien Weevils fought humans also briefly existed for a time. (TW: Combat)

Not knowing exactly how to use it, part of Torchwood 3 team used the Rift Manipulator in order to rescue two of their number out of the past. (TW: Captain Jack Harkness) The resulting disturbance caused disruptions in time to occur all over Earth, especially in Cardiff. Then persuaded by Bilis Manger, Torchwood 3 used the Rift Manipulator to repair the damage, but also released Abaddon, a demonic being which killed dozens in the city. (TW: End of Days) Three days later, the Doctor and Martha stopped in Cardiff to refuel, whereupon Jack Harkness, having just left Torchwood 3, hitched a ride on his ship.

Cardiff Bay

 * Roald Dahl Plass, under which Torchwood 3 is situated, is a public plaza located in Cardiff Bay.

Splott

 * Splott is the suburb of Cardiff in which Sean 'Bernie' Harris lived. (TW:Ghost Machine)
 * Gary used Splott as an example of where Eugene Jones could have potentially met the bidder for his Dogon's sixth eye (TW:Random Shoes)

Real World

 * Brian Badcoe was born in Cardiff.
 * Doctor Who, Torchwood and The Sarah Jane Adventures are filmed in Cardiff.