What is the most expensive MTG?

Excuse me, but I'm curious about a specific topic in the world of collectibles. Can you tell me, what is the most expensive Magic: The Gathering (MTG) card or item out there? I've heard stories of incredibly rare and valuable finds, but I'm not sure which one truly holds the title of being the most costly. I'm fascinated by the world of MTG and its intricate market, so any insight you could provide would be greatly appreciated.