“I cannot forecast to you the action of Russia. It is a riddle wrapped in a mystery inside an enigma: but perhaps there is a key. That key is Russian national interest.”

“What we have here is a riddle wrapped in a mystery inside an enigma.”

“All is a riddle, and the key to a riddle… is another riddle.”

“Whoever said that Russia was an enigma inside a something-or-other inside something else, was dead right. I don't understand the place yet.”

“The key point to bear in mind is that Russia cannot be in Europe without Ukraine also being in Europe, whereas Ukraine can be in Europe without Russia being in Europe.”

“Persistence is the key to solving most mysteries.”

“Love was the key to understanding all of the mysteries.”

“A dream is the key that unlocks the mysteries of the waking world…”

“Forgiveness is the key to action and freedom.”

“A sparrow can be as interesting as a bird of paradise, the behaviour of a mouse as interesting as that of a tiger. Our planet is beautifully intricate, brimming over with enigmas to be solved and riddles to be unravelled.”