Most of us understand that the shortest line is a straight line connecting two places. However, this approach is not followed while building roads up mountains or steep slopes. If you get the opportunity to visit the mountainous areas, you will see meandering roads like these.

Some routes leading up the mountain have even become famous across the world due to their twisting and many twists. So, why don’t they create these roads in a straight line rather than zigzag?

The solution is simple: it protects pedestrians’ lives by making it easier for them to walk up hills. In the past, while building a road to the top of a mountain, people would typically bring a donkey and let it climb the slope to investigate first.

They discovered that this animal did not choose the shortest straight path, but rather a path with a slight incline. Because this is the slope where they feel comfortable (approximately 8 to 10 degrees). The exploration team will create based on the animal’s route, after measuring and sketching it.

In terms of science, the reasoning is as follows. Long periods of running uphill in a straight path might impair drivers’ vision. This may easily lead to distraction and danger. Curvy and twisting roads will help drivers concentrate more.