https://en.wikipedia.org/wiki/Anders_Behring_Breivik
But of course we know that the terrorists are radical Islamists. Of course they are. They learned during the European colonization of North Africa and the middle east that terrorism is effective. They learned during the destruction of Palestine that terrorism is effective. They learned (quite literally) from the US during the proxy war with the USSR in Afghanistan that terrorism is effective. They learned during the partition of India that terrorism is effective.
There's not much question here.
And like the Sikhs and the Hindus terrorizing one another...or the Irish Republican Army terrorizing the Protestants in Great Britain....or Bader Meinhoff Red Army Faction terrorizing Germany, the Islamists know that nothing catches the attention of media and citizens like some good old fashioned slaughter. And over the years, Russia, China, the US, Britain and France, not to say Israel, India, and a host of African countries have all trained and financed terrorism in conflicts all around the globe. Covertly and overtly.
And it is all of this and all of that, that has resulted in us being where we are today.
Which is a sad day. It isn't as sad as at the height of the Second World War where the 'civilized' western nations were slaughtering one another by the millions between 1938 and 1945....but it isn't nearly as out of control as that period either.
What most people today lack is simple perspective...and certainly...as I can guarantee in your case, the understanding and perhaps even the ability to understand how each point in time is simply the culmination of centuries of historical conflicts....and tomorrow and next week and next year it will still be the same. We are doomed to keep fighting 3500 year old tribal war against one another until we finally discard all religious cults and bronze age texts and antiquated ideologies.
The one thing to bear in mind is that the WWI...only 100 year ago, was the conflict between the medieval and the modern mass industrial age. Many parts of the world have never experienced this scale of upheaval until the last few decades and many rural tribal societies still have yet to come into this same age.
Europe, America and much of Asia did not get to 2015 without some of the most breath-takingly savage conflict in the past 100 years that no one on this board carrying on about 129 people killed in Paris can even begin to comprehend. It is a testament to the resilience and adaptabilty through capitulation that now allows us all to live in relative harmony with one another.
There may be yet hundreds of thousands of lives lost before the different sects of Islam reach that accommodation with each other and with the rest of the world as well.
That is the simple harsh reality.