The sand dunes at Port Stephens, NSW are so big that it could easily be mistaken as a desert despite it being very close to the coast. This picture was taken on our way to a sandboarding spot deep inside the dunes. We are not sure what those pyramids are for. May be for parking camels?
Those pyramids at Stockton sand dunes are tank traps put in place in WW2.
Some info here on them http://www.thelongpaddock.net/stockton-beach.html
There are some under the main beachfront as well
https://www.theherald.com.au/story/3082408/heavy-seas-reveal-tank-traps/
Thanks! That's good information. Learn something new everyday! (actually I feel kind of silly now as these things actually have such a serious use). Thanks for pointing it out!