Practical and hardly any fun, I'd start looking for a local charity I trust. I have one in mind but I'd get a lawyer and hire a couple experts I trust on charity management and basically private detective them.

Once I had one charity I was happy with I'd start feeding it what it needs. In this example, it's a local food bank style community center, so I could blow that place up with maybe 10 million.

I'd be fairly involved for the next 6-12 months as things got going, while also researching and finding the next, larger scale charities. Most of the money would sit in fairly safe investment accounts and depending on what I learned over the first 1-2 years I'd try and have it all out into the world within 15 years.

When I signed the last cheque for the last couple million, I'd hope to have a coalition of well funded, well run charities all over the world that would have the cashflow to maintain their new service levels and the oversight to continue that good work for the next 100 years.