I recently learned that there is one wallet in the world with 1 million BTC attached.
That's an assumption, it's not confirmed. (And it'll never be)
I would say the assumption is wrong... The top reach bitcoin address is public information, and right now the address with more bitcoin is this one: 34xp4vRoCGJym3xR7yCVPFHoCNxv4Twseo with 143528.45848982 BTC
So, 1 million BTC wallet is what we call 'FakeNews' but what is real is the information about how many Bitcoins Shatoshi Nakamoto Has, and in theory, he has a little more than 1 Million.