How did the Hyde Park concert compare to its predecessor at Wembley Arena in 1985?
We asked three readers of the BBC News website who attended both concerts to tell us their experiences of Live Aid and Live 8.
Obviously I wore my original Live Aid T-shirt. I was very pleased that it still fitted me 20 years on.
Paul wore his Live Aid '85 T-shirt
It was a great deal more difficult getting Live 8 tickets than Live Aid passes.
In 1985 I heard on the radio that a concert to raise money for famine relief in Africa would be 'the event of the summer'.
I rang the ticket line and they asked me how many I wanted. I bought four and then had to convince some friends to come with me. They weren't keen at all.
I'm so pleased that I won a Live 8 ticket. Had I not, I had already decided that I could afford £500 to buy one.
There was no way I could miss out on this concert having been there at Wembley 20 years previously.
The acts were superb. Robbie Williams nearly stole the show, REM's Everybody Hurts was very moving and the original video with the Who's Gonna Drive You Home? soundtrack was as emotional this time round as last.
The crowds were very similar. Perhaps a few different hairstyles, less mullets and more skinheads in 2005, but the same banter and good natured camaraderie.
But there was definitely an older, more mixed, crowd this time round. 'Oldies' and second timers like myself helped boost the average age.
The whole operation was much more professional but that caused the event to lose some of its predecessor's charm.
The Hyde Park crowd
The fact that alcohol was banned was also different from Live Aid - in the 1980s there was less worrying about binge drinking.
However they never tasted our half litre cola bottles for traces of Bacardi on our way into Hyde Park.
I was surprised that there was no anthem for Live 8. In 1985, in the baking hot July weather, we belted out Do They Know It's Christmas? and didn't think it slightly strange.
But the biggest difference is that in 1985 we didn't really have any idea how big it would become. It just grew massively afterwards.
I'm so privileged to have been part of it. I've been involved with something to be proud of, and lucky to have been there to seeing history being made twice.
The acts were amazing but there was no one to rival Queen in 1985.
I never thought I would say this but Robbie Williams was absolutely brilliant.
The crowd had been booing Mariah Cary - who had a diva hissy fit about water and a microphone stand - and they started chanting for Robbie.
Usually after one act, there would be a lull until the next band came on, but the crowd really wanted Robbie.
Williams 'nearly stole the show'
When he appeared the place erupted.
Throughout the concert, there were some technical hitches that really impacted on our enjoyment. The sound was dreadful. It was far too quiet.
This was made worst by the racket of people chatting on their mobile phones.
Now there's a difference from 1985. You would have to bring your own personal antenna to make a phone call from Wembley in the 1980s.
I was surprised how well the presenters went down with the crowd. When they announced Brad Pitt, people who were queuing for drinks just turned and started running back towards the stage to see him. He got the biggest cheer - an actor at a music concert!
Another difference was the "golden circle". There were no priority passes at Wembley, everyone got a ticket and got on with it. It annoyed me how big the circle was. They had loads of room and the rest of us were stacked up like sardines right to the perimeter fences.
Preferential treatment at a charity concert doesn't seem right.
At Wembley the acts were all a real 80s sound - the bands of the time. Although 2005 had a more impressive line up, it seemed to span musical tastes and alienated some of the audience.
There were too many people who were just there for the music, and to see their favourite bands.
When Pink Floyd came on and The Who, a lot of young people started to leave. That's fair enough but there wasn't that kind of attitude at Wembley.
I found the behaviour of people in the crowd totally unacceptable. As the musicians were talking about peace, starvation, poverty and changing the world, people were throwing litter on the floor and discarding half eaten food. It was disgusting.
At least at 1985 we believed we could make a difference and were committed to the cause. But that attitude was totally lacking at Hyde Park.
At Live Aid I remember the surge of excitement when we were told "in 10 minutes we are going live to the planet".
It really felt like the world was watching us and although at the time we had no idea, that turned out to be true.
It was different at Live 8. U2 and Paul McCartney just wandered out and started playing, and the crowd were taken back. The songs were great but there was no build up.
Julie Haggis at Hyde Park
There was also confusion about who was actually on stage and what was being shown from other Live 8 concerts around the world.
When Status Quo were on the screens I thought for a minute they were there, but they were just repeating the Live Aid opening song from Wembley. It was all a bit strange.
The original Africa film, with the soundtrack Who's Gonna Drive You Home? was a pivotal moment for me.
Silence fell over the audience as people watched the film.
When the young girl was brought out and she looked so beautiful, I really felt that something could be done about the suffering and poverty.
Bob Geldof and all the others have done so much for charity. I heard he had told the performers not to mention the G8 leaders by name and I was glad that there were no personal pleas.
Madonna shared the stage
They have really raised their game since Live Aid.
Awareness of poverty is now at a totally different level to 1985 and that will pressurise world leaders into doing something to help.
I found the attitudes of the crowd different to Wembley in 1985. They were more cynical and more impatient for the music. People were chatting and moving round.
But at Live Aid we were all seated - well mainly standing up and dancing in front of our seats - and turned towards the stage so we were very focused on the action.
Live Aid was a more intense experience.