Which is the No 1 expensive chocolate?

Can you tell me which chocolate is considered the most expensive in the world? I'm genuinely curious to know what makes it so pricey and if there's anything unique about its ingredients, production process, or even its packaging that sets it apart from other luxurious chocolates. I'm fascinated by the world of high-end food products, and I believe that such an exquisite item deserves some exploration and understanding.