Facebook founder Mark Zuckerberg and his wife Priscilla Chan says they'll give away 99 percent of their 45 billion dollar fortune to charity.
They made the pledge as they announced the birth of their baby girl Max.
In an open letter to her, they wrote about creating a better world for their daughter - and all children.
Sky's US Correspondent Amanda Walker says it'll go down in history as one of the most generous charitable pledges.
Charities are in for a massive windfall, as Helen Vaughan reports.
