The Sydney Harbour Bridge was an iconic part of the Sydney skyline. From many vantage points, it could be glimpsed alongside the Sydney Opera House. In the 1970s, the bridge was destroyed by the Daleks, who had launched missiles from stolen nuclear submarines. The Daleks attacked Sydney with the hope of turning it into a base from which to take over the rest of the world. Since they carried out the attack by sub, they would have to sail into the Harbour to make their landing. This required that they sail their submarine underneath the remains of the bridge — where the Third Doctor and Lt Davis had a trap in store for them. As the submarine passed underneath, Davis sent down an electrically-charged cable to the deck, which killed all the Daleks. (COMIC: *Sub Zero)