The United Nations says a funding crisis is putting millions of people in danger. An internal review of the organisation is also reported to be looking for drastic cuts and reforms. That's after its bigger donor - the U.S. - slashed foreign aid. So what is next for the UN?

The United Nations says a funding crisis is putting millions of people in danger. An internal review of the organisation is also reported to be looking for drastic cuts and reforms. That's after its bigger donor - the U.S. - slashed foreign aid. So...

Why does the United Nations face a funding crisis?