Sydney

Sydney was a city located in Australia.

In the 1970s, a group of Daleks based underneath Antarctica captured a nuclear submarine and used it to destroy Sydney. Their plan to use the ruined city as a base from which to convert Humans into slaves and conquer Earth was defeated by the Doctor with the aid of Lt. Davis. (TVA: *Sub Zero)

The destruction of Sydney was not reflected in any other story.

BOSS, the villian of The Green Death proposed that after he conquered the world, they would get the Sydney Orchestra to play at his victory ceremony

On 14th July 1993, the Doctor met with 37-year-old Dorothée in a café in Glebe, a suburb of Sydney. (NA: Set Piece)

In 1995, the Doctor, Ace and Bernice Summerfield visited the interdimensional café in Glebe. (NA: Set Piece)

In 1996, the Doctor, Chris Cwej and Roz Forrester visited Sydney for a week. (NA: Return of the Living Dad)

The Doctor bought a beach-house in Sydney while his house in Kent was being painted. (NA: Sleepy)

In 2009 Sydney was one of the cities celebrating when Earth was returned. (DW: Journey's End)

In 2010, The Doctor and Majenta Pryce investigated an incident where a Chronal Wave caused the passengers of an aircraft to age several hundred years. (DWM: The Age of Ice)

In 2096, Sydney was an independent city-state. (PDA: The Indestructible Man)