What the most expensive dog?

So, I'm curious to know, when it comes to the world of dogs, what exactly is considered to be the most expensive breed? Is it a rare, exotic breed that only the wealthy can afford? Or is it a dog with a specific lineage or bloodline that commands a high price tag? And what makes these dogs so costly? Is it their unique appearance, their temperament, or something else entirely? I'm eager to learn more about this fascinating topic, so please, do tell!