Norway is rated the most peaceful nation on the planet, with Iraq the least. The GPI uses a variety of indicators to determine the entire list.
Each nation has detailed ratings by the GPI on a variety of peace factors (the USA – 96th – for example). Further click-thru will reveal what each parameter is and how it was calculated.
Scandinavia tends to do well on these sorts of surveys (like privacy), and in fact Europe in general.