The Blue Lake sits in an extinct volcano. It is actually one of four crater lakes in Mt Gambier. One of the others is just on the other side of the road. For most of the year it is a regular deep blue colour but in November, and almost overnight, the colour changes to a deep, intense blue. This normally lasts until February and by March it has returned to its normal colour.
All three of the above photos, when placed side-by-side, give a panoramic view of the lake.
The Pumping Station below is still used to provide fresh drinking water for Mt Gambier.