Find the rightful owner
As Emo Philips once said, "I was walking down fifth avenue today and I found a wallet, and I was gonna keep it, rather than return it, but I thought: well, if I lost a hundred and fifty dollars, how would I feel? And I realized I would want to be taught a lesson." Though to be frank, if it was on the news and they asked for a return, I'd return it.
Just being realistic... I could pay off my student loans. Kind of paradoxical, but if it was a wallet with the money and an ID, I'd likely return it.
That much money.... keep it
I was walking around and found $120 dollars one time. I kept it, I immediately spent a portion of it. If I found $1million, I would just have to be a lot more careful how I spent it, to avoid the taxman that's trying to steal it from me.
Because i CouLd BuY The mostest MINECRAFTTTTT
I wouldn't reach out to find the owner, but if they found me I'd turn it over
Unless I can't find them.
I take it to the authorities
If someone returned my $1,000,000 I'd feel pretty inclined to give them a reward...