The Eurasian Gradient
At school, we have been taught that the boundary between Europe and Asia runs along the Ural Mountains for the most part. Many years later, during my two journeys (in 2018 & 2019) from Moscow to Beijing on board the Trans-Siberian and Trans-Mongolian Railway trains, I have witnessed that the said border isn't that obvious. And where would you draw the line, if you dare?