The aim: The human desire to find the "key" and to own it has the sacred meaning - knowledge of self and the world, opening all the doors, release and independence. The main role of the key lies in its important purpose - to open or close access to anywhere or anything. Thus, in the pictures of Judgment Day at the end of the world a big key serve to lock the devil for a thousand years in the pit of the abyss (Revelation, Chapter 20: 1). Key that is capable to remove material or spiritual obstacle in our way symbolizes the entrance, access, promotion, freedom of action and choice, cognition. Duality, the ability to unlock or lock makes a key the symbolic object that embodies both the resolution and the binding force of its owner. Each key is a kind of clue to the mystery.