Why is the enlightenment considered the turning point in world history

My answer will seem very cliche, but it was the time when people started to think more openly. They began to ask questions they didn't dare to ask before, not letting religion or tradition hinder them from getting the answers they needed. Because of this, the study of science was starting to experience a sort of "birth". Theories were formulated, later proven by experiments and such.

Prince henry the navigator is the man you're looking for.