Why are runes so powerful?

Could you please explain to me the reasons behind the immense power attributed to runes? I've heard so much about their enigmatic abilities, but I'm still struggling to grasp their essence. Are they encoded with ancient secrets or are they merely symbols with deep cultural significance? How do they manage to wield such influence and what is the source of their might? I'm particularly fascinated by the stories of rune magic and its ability to unlock unseen forces. Could you enlighten me on this matter?