At her home in the U.K., Malala Yousafzai reads her letter to the missing Nigerian schoolgirls. Courtesy of Malala Fund hide caption

itoggle caption Courtesy of Malala Fund

Campaigners marched Monday in Nigeria's capital of Abuja during a silent protest to raise awareness about girls and boys abducted by Boko Haram. Sunday Alamba/AP hide caption

itoggle caption Sunday Alamba/AP

No one knows how many children have been affected by the spread of Boko Haram across Nigeria and neighboring countries. This photo shows the school uniforms of the girls kidnapped from a school a year ago. Glenna Gordon/Glenna Gordon for NPR hide caption

itoggle caption Glenna Gordon/Glenna Gordon for NPR

Supporters of Muhammadu Buhari celebrate ahead of their candidate's victory, in Kano, Nigeria, on Tuesday. Ben Curtis/AP hide caption

itoggle caption Ben Curtis/AP

Nigerian electoral officials collate results at a polling station in the oil rich Niger Delta, Port Harcourt, Nigeria on Sunday. Millions of voters headed to the polls in the Nigerian general elections after being delayed for over a month. Tife Owolabi/EPA/Landov hide caption

itoggle caption Tife Owolabi/EPA/Landov

Nigeria's President Goodluck Jonathan, left, and opposition candidate Gen. Muhammadu Buhari, right, prepare to sign a renewal of their pledge to hold peaceful "free, fair, and credible" elections, at a hotel in the capital Abuja, Nigeria, on Thursday. Ben Curtis/AP hide caption

itoggle caption Ben Curtis/AP

A man hammers a wall with elections posters at an open market in Kano, Nigeria, on Friday. The country is preparing for presidential elections on Saturday. President Goodluck Jonathan faces former military ruler Muhammadu Buhari and 13 other candidates in what is seen as the closest presidential race since the end of military rule in 1999. Goran Tomasevic/Reuters/Landov hide caption

itoggle caption Goran Tomasevic/Reuters/Landov

Nigerian President Goodluck Jonathan speaks during the inauguration ceremony of the 750 megawatt power station in the southwestern Ogun state, Nigeria, last month. In an interview with the BBC Friday, he said he hopes to retake all territory seized by Boko Haram within a month. Jiang Xintong/Xinhua/Landov hide caption

itoggle caption Jiang Xintong/Xinhua/Landov

The most recent propaganda videos from Boko Haram have higher production values than in the past and other similarities to ISIS-produced videos. Boko Haram/Sendvid hide caption

itoggle caption Boko Haram/Sendvid

Rabia Salihu Sai'id, Mojisola Usikalu, Nashwa Eassa, Mojisola Oluwayemisi and Dang Thi Oanh won the Elsevier Foundation Awards for Early Career Women Scientists in the Developing World Alison Bert/Elsevier Connect hide caption

itoggle caption Alison Bert/Elsevier Connect

An armored vehicle used by Boko Haram militants captured by the Nigerian military in Maiduguri, Borno state, late last month. The extremist group appears to be expanding its operations into neighboring countries in an effort to establish an independent Islamic state. EPA/Landov hide caption

itoggle caption EPA/Landov

In this 2012 photograph, Adamu Ali carries his 4-year-old son, Omar, who was stricken with polio earlier that year. They live in the Nigerian village of Minjibir. David Gilkey/NPR hide caption

itoggle caption David Gilkey/NPR

An official stands in front of relief materials at a camp for displaced people in Maiduguri in Borno State last week. The town, where many have gathered after fleeing Boko Haram attacks, is now said to be under assault from the Islamist extremist group. Reuters/Landov hide caption

itoggle caption Reuters/Landov

A group of Nigerian traditional hunters and vigilantes gather on vehicles on their way to engage Boko Haram militants in Mubi from Yola, Adamawa State, in November. The hunters have being assisting the Nigerian military in their fight against the Islamic insurgents. STR/EPA/Landov hide caption

itoggle caption STR/EPA/Landov

Maureen B. Kabrik, a "#Bring Back Our Girls" campaigner, speaks during a sit-out meeting in Borno in support of the release of more than 200 Nigerian schoolgirls in August. Boko Haram militants, who seized the girls last April, have reportedly captured a key military base in the region. Afolabi Sotunde/Reuters/Landov hide caption

itoggle caption Afolabi Sotunde/Reuters/Landov

Dr. Ameyo Adadevoh and her only child, Bankole Cardoso. Even after she was diagnosed with Ebola, her son says, "Her morale was not low. She is such a fighter." Courtesy of Bankole Cardoso hide caption

itoggle caption Courtesy of Bankole Cardoso

Adebisi Alimi, an actor-turned-activist, was the first person ever to come out as gay on Nigerian television. He now shares his story when he speaks up for the rights of the LGBT community. Claire Eggers/NPR hide caption

itoggle caption Claire Eggers/NPR

Members of the Abuja "Bring Back Our Girls" protest group sit during a march in continuation of the Global October movement. Once again, Boko Haram militants are implicated in killings and mass kidnapping in northeastern Nigeria. Afolabi Sotunde/Reuters/Landov hide caption

itoggle caption Afolabi Sotunde/Reuters/Landov

A sculpture of oil workers in Caracas, Venezuela. The country is heavily dependent on oil exports, and falling oil prices have had a ripple effect on the country's already troubled economy. Ariana Cubillos/AP hide caption

itoggle caption Ariana Cubillos/AP