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.)
I'd go to universities all over the world and ask teachers and students to show me their projects and ideas to help society. There are some incredibly smart people out there that could change the world if we helped them.