The Great Dog Fence
The Great Dog Fence, or Dingo Fence, was built to keep dingoes (wild dogs nowadays) out of the relatively fertile south-east part of the continent (where they had largely been exterminated) and protect the sheep flocks of southern Queensland. It stretches 5,614 kms (2,500 km long in Queensland) from Queensland to South Australia. Don’t forget to close it behind. Keep those dogs out!