What is the most expensive Hi Fi?

Can you tell me, what exactly is the most expensive Hi Fi system on the market right now? I'm particularly interested in knowing what features or technologies make it so costly, and whether or not the price tag is justified by its sound quality and overall performance. Is it a standalone unit, or a combination of multiple components? Additionally, how does it compare to other high-end audio systems, and is there a specific brand or model that stands out as the ultimate luxury in Hi Fi audio?