Poland's border with Russia — Stalin's thumb legend and the real story behind the straight line

Poland's border with Russia (the Kaliningrad Oblast) is an almost perfectly straight line, unlike any of the country's other borders, which follow rivers or mountain ridges. It resembles the post-colonial borders of Africa and the Middle East, drawn by great powers without regard for local populations. A popular legend holds that the line was traced by Stalin's finger or thumb on a map.