What penny just sold for $1 million?

Could you elaborate on the remarkable event that recently occurred in the world of cryptocurrency or rare coin collecting? Specifically, which penny was sold for an astonishing $1 million, and what factors contributed to its remarkable valuation? Did it possess any unique historical significance, rare minting features, or was it simply a matter of market speculation and demand? It's intriguing to think about the potential reasons behind such a substantial price tag for what was once a small-denomination coin.