"This has been a devastating year for children," the United Nations Children's Fund (UNICEF) declared, as the world witnessed one of the worst conflict-ridden years that affected millions of children.
From the Gaza war that killed hundreds of children, and the families and children displaced in conflict zones in the Middle East, to the Boko Haram kidnapping of Chibok schoolgirls, and the most recent incident of the Peshawar school attack on 16 December that left 132 school students dead, children have borne a heavy brunt of conflict and terrorism.
"Children have been killed while studying in the classroom and while sleeping in their beds; they have been orphaned, kidnapped, tortured, recruited, raped and even sold as slaves. Never in recent memory have so many children been subjected to such unspeakable brutality," UNICEF Executive Director Anthony Lake said in a new report released earlier this month, even before the Peshawar carnage.
According to the report, up to 15 million children were caught up in conflicts in the restive regions of Iraq, Syria, South Sudan, the State of Palestine, Central African Republic, and Ukraine.
More children are likely to fall victims of increasing conflict, as UNICEF highlighted that as many as 230 million children are currently living in countries affected by conflict.
Some of the most disturbing incidents that affected children this year are as follows:
Peshawar School Attack: The most recent incident of the Peshawar school attack on 16 December that left 132 school students dead was one of the deadliest such attacks on children anywhere in the world, perpetrated by the Taliban's Pakistan faction.
The school attack sent shockwaves across the world over the cold-blooded brutality of the terrorists, who targeted students in an army school to seek revenge against the Pakistan military's offensive on militants.
Terrorists stormed into classrooms and shot dead students after lining them up, reports suggested, and stories of horror poured in in the following days as survivors gave chilling accounts.
Gaza War: Earlier this year, the 50-day Gaza conflict, said to be the deadliest assault by Israel, had killed more than 2,000 Palestinians, of which 538 were children, according to UNICEF.
54,000 children were left homeless, and 3,370 were injured as bombs pounded the Gaza strip.
One of the most heart-wrenching incidents from the war was when four children playing on the beach were killed by an Israeli air strike.
Four cousins, all under 15, were playing football on the beach in Gaza when two missiles struck this July, killing them all instantly.
The conflict itself was said to have been triggered by the gruesome murders of Israeli and Palestinian teenagers.
Islamic State Takes Yazidi Girls as Sex Slaves: The rise of the brutal Islamic State, previously known as ISIS, in Syria and Iraq had a deadly impact on the children in the region, especially on the minority communities of Yazidis and Christians, which were persecuted by the terror group.
Even while thousands of Yazidis fled their homes and took refuge on Mount Sinjar for months, several were kidnapped by ISIS militants, who took young girls as sex slaves.
Some shocking reports revealed that Yazidi and Christian girls as young as one to nine years of age were being sold for a price of $172 in Iraq.
Traumatic accounts of some of the girls raped by the militants
There were also disturbing reports of Islamic State beheading children or forcing them to watch gruesome killings.
At least 700 children are believed to have been maimed, killed or even executed this year in Iraq, according to UNICEF.
Syrian Conflict: In Syria, more than 7.3 million children were affected by the conflict between the Syrian regime and anti-government forces, including 1.7 million child refugees, according to UNICEF.
The United Nations said there were about 35 attacks on schools in the country this year, which killed 105 children and injured nearly 300 others.
Boko Haram Kidnappings: The Boko Haram militants in Nigeria, who are against Western education, kidnapped more than 200 schoolgirls from Chibok this April, whom they threatened to sell as sex slaves.
Reports emerged that many of the young girls had been converted to Islam and married off to militants, while some reports claimed the girls were also being used as suicide bombers.
The kidnapping led to the global #BringBackOurGirls campaign, which saw prominent political figures and film celebrities take up the cause to free the girls.
The Boko Haram militants also kidnapped 100 boys from a village in Borno State in Nigeria this year.
Conflict in Africa: 2.3 million children in the Central African Republic have been affected by the conflict, and a staggering 10,000 children are believed to have been recruited by armed groups over the last year, UNICEF said.
The number of children killed or maimed in the region has tripled since 2013, with more than 430 such incidents recorded.
The statistics are even more disturbing in South Sudan, where 600 children have been killed and over 200 maimed this year, and around 12,000 children are now being used by armed forces and groups.
If not conflict, the Ebola epidemic wreaked havoc in Western African countries this year, leaving thousands of children orphaned and an estimated 5 million out of school.
Sewol Ferry Tragedy: While the Sewol ferry tragedy was not a conflict-related incident, the capsizing of a ferry on 16 April that killed 300 school children off South Korea's coast saddened the world, and reports of mismanagement by the crew led to widespread anger.
Several crew members, including the captain, abandoned the sinking ship, leaving hundreds of children trapped on board.
As the year ends on a grim note for children around the world, it puts in perspective the effort required to make 2015 a better year for them.
"The world can and must do more to make 2015 a much better year for every child. For every child who grows up strong, safe, healthy and educated is a child who can go on to contribute to her own, her family's, her community's, her nation's and, indeed, to our common future," UNICEF said.