Ding - Dingaling - Ding - Ding - Chink!! The lights are flashing all over my little geek-pinball-table with this one! I am inducted into the annals of Geekgodess!! Hah!!
They have varying names: sub-floor vents, air vents, air bricks. Whichever, I have chosen ones from older buildings - late 19th, early 20th century. Vents in the 21st century are a little more pedestrian.
Top: Supreme Court, St James Road
Left: Town Hall, Druitt St entrance
Right: Caraher Lane, The Rocks
Top left: Sydney Hospital, Macquarie Street
Top right: Commonwealth Bank, Martin Place
Lower left: GPO, George Street entrance
Lower right: Bible House, Bathurst Street
Top left: Mitchell Library, facing Shakespeare Place
Top right: Sydney Hospital, Nightingale Wing
Last: Lands Title Office, Prince Albert Road