Occupying almost an eighth of the world's land, Russia is a vast expanse that extends from maritime Vladivostok in the southeast to the icy Kola Peninsula in the northwest. As the world's largest country, Russia has historically had difficulty defending its borders. From 13th-century Mongol conquests across the Great Eurasian Steppe to the Nazi invasion of WWII, Russians have constantly faced threats of foreign incursion. Their cities are also quite spread out, with ample agricultural land often located far from major population centers. Transporting crops from the breadbasket regions to the people before they spoil is tricky and costly.