Thorntons Scent Bottle

Visitors to Sydney will have no doubt driven or walked right past one of the City’s most innovative objects without even realising it.
Right there on Elizabeth Street, at the junction of Bathurst Street lays a tall structure known as "The Hyde Park Obelisk."
To the passer by this tall spire is of little interest and indeed to the avid traveller who may have seen a similar structure in Paris, London or New York it would seem no different.
However this sandstone monument hides a secret that literally reeks with Australian pride.
Erected in 1857 by then Sydney Mayor George Thornton, and modelled on the famous Cleopatra's Needle of ancient Egypt, with a beautiful sandstone base and fine-filigreed bronze pyramid at the top, it was known in earlier times as Thornton’s Scent Bottle.
For you see, it was built over the top of Sydney’s main sewer line, to be used as a vent to eliminate noxious gases.
Paris, London and New York all have Obelisks that were presented to each city by Egypt, but Australia has the only one that is on top of a sewer, surely a testament to the ingenuity of a fast growing colony in the antipodes.
It was the very first sewer vent in the Sydney sewerage system and the only one made of sandstone.
The system, then known as Bennelong Sewerage Works, was a combined waste water and stormwater system, which drained to an outlet at Bennelong Point where the Sydney Opera House now stands.
In the late 1880's the Bondi Ocean Outfall was built, and all dry weather flow was diverted to the Bondi Treatment Plant, but wet weather flow was still into the harbour via Bennelong Point.
The Hyde Park Obelisk was integral in stopping gas build up in the underground sewer and in fact one account from around 1894 suggested the following:
"The Obelisk causes a splendid draft in Pitt-street sewer - the foreman reports it is difficult to keep a candle alight when working in same. The work done by the small staff is considerable (the staff consisting of a plumber and a youth."