Overall, the world is 5 percent less peaceful than in 2008, with war-ravaged Syria's global peace index declining the most, by 70 percent.
North America is the second most peaceful region in the world, although the United States ranks 100th out of 162 countries. The U.S. ranks especially high in the nuclear and heavy weapons category and with its jailed population, all indicators of a non-peaceful nation.
"The U.S. has one of the highest incarceration rates in the world, we have fairly high homicide rates and a wide availability of small-arms," said Breslauer.
"This fall over one year that Syria has experienced is the largest fall we've seen in the index thus far," said Michelle Breslauer, vice-president of U.S. programs at the Institute of Economics and Peace, to CBSNews.com.
The major outbreaks of violence in the Middle East in the past few years have also seen Afghanistan return to the bottom of the list. Somalia moved up the list for the first time in two years, to second-least peaceful country in the world.
The number of deaths from internal conflicts has also risen significantly.
In the past year,claimed twice as many lives as the conflicts in Iraq and Afghanistan combined.
It's not all bad news, though. In the list of countries recently affected by war, Libya, steadily recovering from its civil war which saw the removal of dictator Muammar Qaddafi, has the highest improvement in peace score, climbing up three places to 145th.
"Libya's one of the largest risers this year but that's really a reflection of the fact that it was coming from a less peaceful starting point," said Breslauer. "The risers that we see each year, it's not that they're dramatically peaceful, it's that their move signifies the fact that they're emerging from conflict."
The most peaceful region in the world is Europe, which has 13 of the top 20 most peaceful countries.
All the countries in Europe score higher than average, except.
The top three most peaceful countries are Iceland, Denmark and New Zealand. Small and stable democracies make up the top ten most peaceful countries.
Central America is home to some of the world's most violent countries; Honduras has the highest homicide rate in the world, with 92 homicides per 100,000 people. El Salvador comes in next, with 69 homicides per 100,000 people.
"One of the main takeaways from the index this year is this move from wars between states to violence within society. So this rise in homicide rates and this rise in internal conflicts is something that really shakes the security of people in societies," said Breslauer.