Updated 16 March 2004, 11.59
The Madrid bomb explosions have rocked the world, bringing the horror of terrorism back to us all.
And not since the Lockerbie plane bombing in 1988 has there been such a massive loss of life from a terror attack in Europe.
So how have YOU reacted to it? Are you feeling scared, emotional - or both?
Perhaps you know someone who has been directly affected by the blasts or was in Madrid at the time.
Share your thoughts and feelings by e-mailing us here now.
Unfortunately this topic is now closed but there are Comments pages on other subjects on the main Chat index.
I think that what those people did to Madrid is awful. In the news there is always stuff to do with death. If people focused their attention on the people who need it most instead of killing them then we might get somewhere.
Laura, 13, Ringwood
Terrorism should be stopped immediately! I don't want it to happen here or anywhere else in the world.
Pete, 8, London
My dad always used to tell me, 'Man's inhumanity to man is the worst crime'. This is a perfect example.
Ceri, 13, Colwyn Bay
I think it's disgusting that someone would actually even think of killing anyone else. My heart goes to Spain and all those grieving for their lost friends or relatives and those responsible should confess and face the consequences.
Scarlett, 13, Essendon
It is scary to think that that sort of thing could happen anywhere. And I feel very sorry for the families of the victims.
Samantha, 8, Galway
I think the attack on Madrid was immoral, I just can't get my head round why people can do this sort of thing.
Stephen, 14, Edinburgh
The bombings in Madrid bring back the horrific memories of 9-11. I can't believe anyone would ever want to cause such destruction to anyone else. It sickens me.
Jessica, 15, Alaska, USA
It makes me so angry and sad to see that things like this happening in the world. Terrorism is an awful thing and I think the people of Spain are coping extremely well.
Rebecca, 11, Liverpool
Why is this happening? It's awful. I wish we could all get along. I am so sorry to the families of the victims.
Sairah, 11, Chester
I don't know how anyone could even think of doing something like that. Terrorism is pointless anyway, what does it show. Only that you're stupid enough to kill innocent people and carry the guilt.
Leah, 11, Stockport
As well as being upset I am completely outraged that in this day and age there are still people that create such devastation. My prayers are with all those who have been affected in any way from this tragedy.
Abigail, 14, Bedford
I can't believe people could do such a thing like it.
Lara, 11, Herts
This is just plain mean! I can't believe that someone would want to kill their own species. I am scared that next London will be attacked. People cause grief to others for no reason, what's the point?
Naomi, 11, Nottingham
I am so sorry for the families who have lost someone. It must be awful to cope with this. Why does there have to be terrorism and murder? But someone will hopefully manage to put a stop to this.
Lana, 9, Middlesbrough
I'm really sad. My heart is with them people at this moment in time.
Tasha, 12, Essex
It is awful what happened on the 11th, all those innocent people that died. All of us are worried that here might be the next target.
Kayleigh, 14, Brighton
My heart goes out to all the people in Spain. It's such a shame that a terrible thing like that can happen to innocent civilians who have done nothing to deserve it. Hopefully one day, someone can put a stop to terrorism.
This has really upset me. I can't believe there are people in this world who would do such a thing to innocent people. My thoughts go to the families and friends of the people who died.
Charlotte, 12, High Wycombe
It's very sad for all those people whose families have died. I just don't know why there are so many terrorists.
Sumi, 10, Leicester
I am upset because all those people have lost family and friends. I am also scared because we don't know where the terrorists will strike next.
Rosie, 10, Falkirk
When you hear of these sort of attacks, you always think that it could never happen to you. The scary thing is that it could and you don't know where it could happen next.
Sophie, 13, London
I think that whoever is doing this should stop, people are getting killed who don't deserve to.
Bethan, 10, London
I can't believe what happened in Spain. Though it's far from home, it reminds me of what happened here in New York. And I'll never forget that.
Kat, 14, New York
I think it is upsetting every time these things happen, but it is hard to imagine the horrific reality before it happens to you. But this sort of news makes you think that it could be you next.
Gemma, 14, Nottingham
The reporter on the news said "some people may find these images distressing" and I thought "ok whatever". By the end of the report I was crying.
Jemma, 14, Wiltshire
It's just wrong. I feel so sorry for all the people who lost family members and friends in the bombing. Let's just hope we can crack down on all these people thinking up these wicked wicked ideas.
Kate, 13, Aylesbury
I think it really makes you wonder why anyone would want to harm so many people and why we can't just live in harmony with each other. But it also makes you wonder if terrorism could soon become something we have to learn to deal with here. It's appalling anyone could want to ruin so many lives and not care.
Becky, 14, Birmingham
It's so awful, and my heart goes out to all the injured people, all the killed people and all their relatives and friends mourning at the loss of their dearest.
Evie, 9, England
I am really worried now because it makes you think that it can happen anywhere. I wish there was no terrorism or anything like that.
Kat, 13, West Drayton
Some of my relatives live in Spain. It's really upsetting for them they rang us and said that it was horrible.
Sara, 12, London
It's really frightening to think that there are still people out there who want to ruin more people's lives. It's just like the New York attacks. All this terrorism has to stop.
Aimee, 12, Derbyshire
I think what has happened is horrifying. Whoever does these things is completely sick in the head. Innocent people are being killed for no reason!!! Which is not fair for them and their families because they have to go through so much heartache.
Sukhvir, 14, Leicester
I think the violence is awful. It makes me cry thinking about it. I wish we could all get along and there would be no wars no fights, anyone with me?
Sarah, 12, Chester
When I heard I first thought it was just a train accident and that there was NO chance of it being a terrorist attack, but when I heard on the news how over 100 people died and that there were bombs, I felt so sick at the thought of it happening so close to us and how we know friends and family there.
Soraya, 15, St Albans
This incident among others is a real eye-opener and makes you think how lucky you are in the world. God bless all those affected by this horrific time.
Gem, 14, Bridgwater
I think it is pointless because they are killing lots of people and devastating lots of families and you never know when they strike again they have ruined the world by what they have done
Ruth, 11, Bedford
It is frightening as Spain on the list of terrorist threats was quite low - we need to make sure the UK and the rest of the world is safe from them and their destruction.
Hannah, 13, Hampshire
I think that it's horrible and in a way I think it's just as bad as 9 11. I'm quite worried as well because a guy in my class is in Spain at the moment.
Hannah, 14, Dublin
It's terrible! I'm really scared that the terrorists will come over to England and do something like 9/11 and the bombs in Madrid.
Catilyn, 13, Hemel Hempstead
This is truly terrible. What gains do the terrorists hope to achieve by this massacre? I was in tears watching the news reports and I'm sure I'm not the only one. My thoughts and prayers are with the victims and their families, the whole of Spain and anyone else suffering from this right now. We now all live in fear, what sort of world is this?
Laura, 13, Southampton
I think it's so sad what happened in Spain. I can't imagine what I would feel if something happened like that in England. It is just so terrifying to know that those sort of terrorist attacks can happen.
I think that it's horrible and in a way I think it's just as bad as 9/11. I'm quite worried because a guy in my class is in Spain at the moment
Hannah, 14, Dublin
I'm scared as it makes you remember what happened on September 11 and brings back horrible memories.
Andrew, 13, Brackley
It makes me sick to see how people who are truly evil can carry out actions like these on innocent people. My prayers are with all injured and the families and friends of those killed.
It is just terrible that people can do such a horrible thing, they should be brought to justice, once and for all.
Matthew, 10, Marple
Wasn't this attack 911 days after the September 11 attack? It's scary to think that all this has been planned, you start to wonder what else they have to do causing terror in the world.
Hannah, 14, Manchester
I cannot believe what has happened. It's a tragedy - my heart goes out to all the hurt and broken families in Madrid. I will never forget. I feel so worried as you never know where they will strike next time.
It's awful - first New York, then Madrid. I'm scared it might be London next. I hate the terrorists because they are cruel and terrible people.
Charlie, 15, London
I'm scared as it makes you remember what problems there are in the world and worry where the terrorists will strike next.
Ben, 13, Chester