On the night of April 14, 2014, Boko Haram - an Islamist militant group operating mostly in northeastern Nigeria - kidnapped about 300 girls from a boarding school in the village of Chibok.
Despite a global outcry over the raid, the Nigerian Government and its backers has struggled to find the girls, let alone free them.
Some of the girls escaped shortly after the attack, but at least 219 girls remained missing until this week, their fate unclear.
Today, Nigerian officials announced that Amina Ali Nkeki, a 19-year-old, had been discovered by locals walking around the Sambisa Forest not far from Chibok.
Nkeki is believed to be the first Chibok girl found since about 60 escaped shortly after their abduction. Exact details remain sparse. Speaking to the AP, Nkeki's uncle Yakuba Nkeki said she was suffering "trauma". He did not elaborate.
In the two years since Nkeki and her classmates were kidnapped, the tale of the Chibok girls has evolved from one illustrating the horrors of extremism to one highlighting the failures of a Government and the fickleness of international outrage.
On that night in April, convoys of Boko Haram fighters had descended on the Chibok Government Girls' Secondary School and kidnapped as many as they could before setting fire to the school.
Gradually, the brazen nature of the crime began to make waves in Nigeria and abroad.
"Bring back our girls" became a slogan after it was used in a April 24, 2014, speech by Oby Ezekwesili, World Bank vice president for Africa. By the end of April, it had evolved into a hashtag - #BringBackOurGirls - that represented a truly global movement. The hashtag was mentioned millions of times online, with well-known figures such as Michelle Obama and Chris Brown lending their name to the cause.
The global attention shone a light on the brutal tactics of Boko Haram, an insurgency founded in 2002 that had been haunting Nigerian society for years with its campaign to impose strict Islamic law.
The world's focus helped propel concerted action, with the United States and other foreign powers sending soldiers and equipment to aid in the fight against Boko Haram. However, as the search for the girls dragged into months and eventually years, their fate became symbolic of the failures of both the Nigerian Government and their Western backers.
With the lack of solid developments in the case, Western interest in the Chibok girls began to ebb. There were some reports of Chibok girls escaping, but they proved false: When the Nigerian Army rescued 300 girls from Boko Haram in 2015, it was later revealed that none of them had been kidnapped from Chibok. It was only last month that new proof emerged - a video showing 15 of the Chibok girls, who said they were "well". They had not been seen since a video from May 2014.
The Nigerian military quickly proved ineffective in its attempts to rescue the girls. Although the Government's campaign to oust Boko Haram from cities and towns was largely successful, the group thrived in the forests and in rural areas, waging a guerrilla war that was hard for a conventional army to contain.
The army itself was accused of committing human rights abuses in its fight against Boko Haram. And despite the attention on the Chibok girls, it soon became clear that they were just part of a far larger number of girls and women who had been kidnapped by Boko Haram with impunity and to little global outrage - perhaps as high as 2000, according to experts. Accounts released by activists even suggested that the military had advance warning of the attack on Chibok but didn't act.
Public anger extended all the way to the top of Nigerian society. President Jonathan Goodluck and his supporters were widely criticised for their response to the crisis, which included arresting protesters, making false or misleading claims about negotiations with Boko Haram, and even appropriating #BringBackOurGirls for a campaign slogan. Goodluck was ousted in March 2015 by former military dictator Muhammadu Buhari, who promised to tackle both Boko Haram and government corruption head-on.
The military had launched an operation in the Sambisa Forest in recent days, according to reports in local media.
However, activists told the BBC that Nkeki was discovered by a vigilante fighter who recognised her, not by troops. She is also reported to have revealed that all of the Chibok girls remain in the sprawling forest except for six, who died. Conflicting reports from her family and activists suggest that Nkeki is either pregnant or was found with a child.
It's not clear exactly what Nkeki endured during her two years of captivity, but accounts from other girls and women who have escaped from Boko Haram painted a picture of widespread violence and abuse. The story doesn't end when they come home, either: Many who have been freed from the Islamist militant group are shunned as "Boko Haram wives" after they return.