Here in Australia there is a long fence.
The fence was built during the 1880s and finished in 1885. Now this fence is the longest in the World!
The fence stretches 5,614 kms (3,488 mile) through thousands of kms of arid land.
Main reason for having this ever so long fence is to keep the dingoes out of the fertile land of our continent to protect the sheep in many areas. This has been partly successful, though dingoes can still be found in parts of the southern states of Australia.
We visited this fence at Coober Pedy where it's very arid.