Russia makes the top 10 list of least peaceful countries.
Russia has one of the highest per capita rates of weapons exports, according to the report, and is highly militarized, which partially explains its rank on this list.
Its engagement in the Syrian conflict increased the country's number of deaths from external conflict, and overall approval of its leadership declined from 35% to just over 30% from 2008 to 2018.
It is the least peaceful country in its region, according to the report.
The Democratic Republic of the Congo is at high risk for severe flooding, contributing to the likelihood of future conflict.
Violence in the DRC is interfering with health workers' ability to treat the country's most recent Ebola outbreak, which has claimed 1,396 lives in that country, according to the World Health Organization.
Gangs and militia groups attack healthcare facilities, killing a Cameroonian doctor working to control the outbreak earlier this year.
Rising violence in Libya, coupled with its high risk for flooding, make it the eighth-least peaceful country in the world.
Violence in the Central African Republic costs the country approximately 47% of its GDP.
Seleka rebels and Anti-Balaka militia members continue to clash in the Central African Republic, pushing the country into chaos and creating an internally displaced population of 620,000, with 570,000 refugees headed to neighboring countries like Cameroon and the Democratic Republic of the Congo, according to Reuters.
Somalia is at significant risk for drought, making the country more prone to conflict.
In 2018, Iraq saw a decrease in state-backed violence and in the number of refugees and internally displaced persons as a percentage of its population.
Still, Iraq deals with significant conflict, both internal and external. The are still remnants of ISIS, despite its official defeat, in part because divisions in Iraq's security forces have undercut efforts to eliminate the group.
Yemen remains the site of the world's worst humanitarian crisis, as it is still locked in a proxy war between Saudi Arabia and Iran.
South Sudan's ongoing conflict, as well as its high risk for climate disaster, contribute to its placement in the GPI.
Syria's conflicts place it high on the list, although it is no longer the least peaceful country.
Syria is now GPI's second least peaceful country in the world. The GPI cites ISIS' defeat in the town of Baghuz earlier this year as key to moving the country from the first spot to the second.
Afghanistan is the least peaceful country in the world, according to the index.
Afghanistan was designated the least peaceful country in the world by the GPI in 2019, supplanting Syria.
Violence in Afghanistan cost it 47% of its GDP, and the ongoing conflict killed 3,804 people last year, including 927 children — the highest number ever in the country, according to the UN Assistance Mission in Afghanistan.
Afghan citizens feel 20% less safe than they did in 2008, according to the GPI. Confidence in the country's military has fallen by more than 31 percentage points since 2013.