The Catalpa Memorial on the Palm Beach foreshore.
The Catalpa incident was an 1876 international incident involving the escape / rescue of 6 Irish Fenian prisoners funded by Irish-Americans from the British colony in Western Australia where they had been sent as convicts. More details below.
https://en.wikipedia.org/wiki/Catalpa_rescue
The folk song The Catalpa was popular in the 1970’s in Australia.