By a dull sewage treatment plant in Melbourne's suburban west, a striking spiral forest unfurls greenery across eight acres of land.
The forest, plonked beside the Altona treatment plant, appears to passers-by as a curious landscape bordering the sprawling facility - but it's actually a piece of world-renowned land art by New York-based environmental artist Agnes Denes.
The piece is named A Forest for Australia, and was created at the Greater Western Water plant in 1998 as part of an international art event called The Bridge: Construction in Process.
While other, more transient installations from the exhibition fell away over time, the land art remains 26 years later - albeit following major challenges including the Millennium Drought and a significant 2015 rejuvenation.
Since the artwork's creation, its inaccessibility has made it a mystery to most Melburnians - until now, as it opens to the public as part of a major design program.
"This unique sculpture has only been open to the public on a handful of occasions," Greater Western Water delivery and solutions manager Jodie Hallam says.
"We're very fortunate to have an internationally-recognised piece of work by a major artist right in our backyard and we don't take our responsibility for this culturally significant artwork lightly."
The land art uses 3700 trees to create five massive spirals, and will be the focus of an Open House Melbourne tour guiding people through the piece's inspiration, climate challenges and revamp.
The land art's original design included river red gums in the centre of the spirals, surrounded by weeping sheoaks and salt paperbark trees to create a staggered, pyramid-like effect.
The way the piece is planted reflects the energy and flow of the large water tanks at the site.
Local initiative Greening the West helped swap out some of the trees in the forest for better-suited species in 2015.
Open House Melbourne works with industry, government and the broader community to advocate for good design across Victoria, and will host the artwork tour as part of its 2024 program.
"It's a really fantastic and unexpected use of government land," Open House Melbourne executive director and architect Tania Davidge says.
"There's a real way to engage people with what we can do in urban environments with under-utilised land; how we can think about climate, regeneration and biodiversity, and do it in a way that's incredibly engaging and incredibly interesting.
"I didn't even realise it was sitting on my doorstep."
The tour will also guide people through the treatment facility itself, uncovering the sometimes unpleasant process of recycling about 2.5 billion litres of water a year.
The water is then used by industry and council for things like maintaining green spaces.
The Open House Melbourne weekend will be held on July 27 and 28.
