The Snowy Mountains Scheme, New South Wales.

The Snowy Mountains Hydro-electric Scheme, built from 1949 to 1974, is well recognised as not just an Australian but a world engineering feat.
Producing hydro-electricity and water for irrigation, the scheme includes seven power stations, 16 dams and 225 kilometres of tunnels and aqueducts.
The scheme helped create multicultural Australia: of the 100,000 workers on the scheme, two-thirds of them were from overseas, coming from 30 different countries.
The Snowy Scheme greatly developed Australia’s manufacturing and technical capacities, and some of the technical breakthroughs on the scheme have since been exported around the world.
The Snowy also brought in its wake a number of environmental problems, such as greatly reduced flows in the Snowy River and other streams.
via National Museum of Australia – Snowy Scheme collection.