A map of all roads:
A map of all railroads:
A map of all navigable rivers:
Considering all of these modes of transportation and the type of terrain, the New Scientist calculated how long it would take, from everywhere on the planet, to get to a city of 50,000 people or more:
They estimate that less than 10% of the world is more than two days from the nearest city. The most remote place, they calculate, is the Tibetan plateau.