Estimated to be 40,000 years old the Brewarrina Fish Traps are a sophisticated and complex arrangement of stones that were used to catch fish as they swam upstream along the Darling River. The Ngemba people used the stones to create barriers and detours for the fish. This would then lead the fish to a narrow passage were aboriginals could easily spear them.The Ngemba people studied fish migration in different seasons and how the river flows to make their traps more efficient and effective. This proves that aboriginals had a broad knowledge of engineering and were beginning to develop farming and agricultural techniques.