I think this would be the Great Wall of China!
although it's actually thought to be much, much longer: over 5000 miles long, if yoiu include natural defensive barriers used in it.
The answer is b. a common currency
hope this helps ! :D
If he makes 3 left turns, he will return home. The men are either burglars or his house guests<span />
Mid ocean ridge
I had this problem
