Holonomy is a prime example of mathematical intuition and creativity - it generalises our school knowledge about the sum of angles in a triangle and led to  `Berger’s holonomy theorem’ from 1954 which turned out to be a  most successful research programme for differential geometry for over 50 years. We are going to tell the story of this development, how holonomy relates to curvature and advanced symmetry concepts, including a small detour to theoretical physics and what Calabi-Yau manifolds have to do with it. We conclude by a small outlook to recent results.