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.
Answer:
The forces which originate from within the earth's crust or inside the earth are called internal or endogenetic forces. The sources providing them energy are the internal heat, chemical reactions taking place within the earth, and the transfer of rock materials on the earth's surface by external forces.
Explanation:
It depends on the mass of the ice,temperature around it and latent heat energy required to melt the ice.
However the furthest a ice berg can travel is estimately 32-40°n/s
