1966 is widely thought of as the year we went decimal.
However, we first ditched the pound and took on the dollar in 1822.
And the note that is evidence of this currency change (pictured) has a strong connection to Queensland, as rare coin dealer Belinda Downie explains.
Unique in private hands this Bank of New South Wales 20 Spanish Dollars is up for private sale.
The asking price is $495,000.