We can't fix all problems but we must fix the ones we can

The most powerful idea that's entered the world in the last few thousand years - the idea of grace - is the reason I would like to be a Christian.

Celebrity is ridiculous and silly and it's mad that people like me are listened to - you know, rap stars and movie stars.

We thought that we had the answers, it was the questions we had wrong.

What turns me on about the digital age, what excited me personally, is that you have closed the gap between dreaming and doing. You see, it used to be that if you wanted to make a record of a song, you needed a studio and a producer. Now, you need a laptop.

It's much easier to be successful than it is to be relevant. The tricks won't keep you relevant. Tricks might keep you popular for a while, but in all honesty, I don't know how U2 will stay relevant. I know we've got a future. I know we can fill stadiums. And yet with every record, I think, 'Is this it? Are we still relevant?'

Sub-Saharan Africa is also home to 400 million of the world's poorest people.