Facebook founder Mark Zuckerberg and his wife Priscilla Chan have said they will donate 99% of their Facebook shares to good causes following the birth of their daughter, Max.
The shares, currently worth $45 billion (£30bn), will go to the Chan Zuckerberg Initiative, which aims to "advance human potential and promote equality in areas such as health, education, scientific research, and energy".
In a touching letter to his newborn daughter, Mr Zuckerberg said he wanted the money to help give Max a better world in which to grow up in.
He wrote: "Your mother and I don't yet have the words to describe the hope you give us for the future. Your new life is full of promise, and we hope you will be happy and healthy so you can explore it fully. You've already given us a reason to reflect on the world we hope you live in.
"Like all parents, we want you to grow up in a world better than ours today."
The Facebook CEO will now take two months paternity leave, but stressed in his letter than he will continue to lead the company for "many, many years to come".