What cause was the focus of Live Aid's fundraising efforts?

Squelle, CC BY-SA 3.0, via Wikimedia Commons

The summer of 1985 saw the biggest concert event ever attempted, with simultaneous shows in London and Philadelphia drawing astronomical viewership. While the music was unforgettable, the driving force behind Live Aid came from a BBC news report that left musician Bob Geldof absolutely furious. What humanitarian crisis inspired this massive fundraising effort?