###      The world's longest borders
Canada-USA : 8,893 km.
Russia-Kazakhstan : 6,846 km.
Argentina-Chile : 5,300 km.
Mongolia-China : 4,677 km.
India-Bangladesh : 4,053 km.
Russia-China : 3,645 km.
Russia-Mongolia : 3,543 km.
Brazil-Bolivia : 3,400 km.