Pretend the $20 million is guaranteed, and if anything will increase slightly over time.
What problems could be significantly improved for $20 million?
(I am dreaming of winning the $1.55 billion Powerball drawling. Then taking the lumpsum, posting taxes, investing, and spending 4% each and every year. I understand that the actual may be more, or less than the started amount.)
After buying my fortress of solitude, and making sure my family is set for generations, I think it would be fun to donate money to random people who are struggling.