What penny was worth $1000000?

Could you elaborate on the penny that was worth one million dollars? I'm intrigued to know which specific penny, under what circumstances, and at what point in history it reached such a staggering value. Was it a rare coin, perhaps a mint error, or was there some other unique factor that contributed to its astronomical worth? I'm eager to understand the story behind this penny and how it came to be worth such an incredible amount.