Hyde Park Obelisk is an obelisk located in Hyde Park in Sydney, New South Wales, Australia. It sits at the intersection of Elizabeth Street and Bathurst Street. Unveiled in 1857 by the then Lord Mayor, George Thornton, it serves as a sewerage vent designed to eliminate noxious gases from the sewer by moving them above street level. It was modeled on Cleopatra's Needle on the banks of London's River Thames. The overall structure is 22 metres high, which comprises a square sandstone base 6.5 metres high. The vent at the top is a filigreed bronze pyramid. It is also jokingly referred to as Thorton's Scent Bottle.