Rescuers search for survivors in the rubble of a collapsed residential building in Makongeni estate in Nairobi December 17, 2014. Three more bodies were recovered on Wednesday night from the building that collapsed in Makongeni estate in Nairobi, raising the death toll to four, Kenya Red Cross has reported. The residential building whose sixth floor was still under construction had allegedly not been cleared for occupation by the Nairobi City County and its owner has been missing since it collapsed. A search and rescue and rescue operation is ongoing for the unknown number of people still trapped under the rubble, Kenya Red Cross also reported. (Photo by Thomas Mukoya/Reuters)

An abandoned tank left by Boko Haram, February 20, 2016, seen on the road to Michika, Nigeria – a town formerly occupied by the insurgents. On April 14, 2014, 300 schoolgirls in the Chibok village in Nigeria were kidnapped by the terrorist group, Boko Haram. Two years later, the majority of these girls are still missing. According to the Global Terrorism Index Report 2015, Boko Haram, which operates mainly in Nigeria, has become the most deadly terrorist group in the world. (Photo by Danielle Villasana)

An unmanned Antares rocket is seen exploding seconds after lift off from a commercial launch pad in this still image from video shot by Matthew Travis of Zero-G News from the press area at Wallops Island, Virginia October 28, 2014. The 14-story rocket, built and launched by Orbital Sciences Corp, bolted off its seaside launch pad at the Wallops Flight Facility at 6:22 p.m. EDT/22:22 GMT. It burst into flames moments later, then plunged to the ground in a huge ball of fire and smoke, but authorities said no one was hurt. The cause of the accident was not immediately known. (Photo by Matthew Travis/Reuters/Zero-G News)

Bosnian worker Sefik Salihovic drives a steam engine in the Bosnian town of Banovici, 140 kms (86.9 miles) north of Sarajevo, on Monday, November 24, 2014. Every day, steam engines over 60 years old, defy their age and still pull wagons of coal from Banovici's coal mine to clients in nearby towns. But in the summer some of them turn into the only tourist attraction this impoverished north Bosnian town has to offer. (Photo by Amel Emric/AP Photo)

Mount Sinabung spews pyroclastic smoke, seen from Tiga Pancur village on October 13, 2014 in Berastagi, Karo district, North Sumatra, Indonesia. Mount Sinabung, which has lain dormant for over 400 years, has been intermittently erupting since September 15 last year, killing 15 people and forcing hundreds to flee their homes. According to The National Disaster Mitigation Agency, more than 3,000 residents are still displaced. (Photo by Ulet Ifansasti/Getty Images)

Chinese relative of a missing passenger on Malaysia Airlines flight MH370 reacts as she weeps outside the main gate of the Lama Temple on March 8, 2015 in Beijing, China. Foreign and local media were prevented by Chinese police from covering the relatives visit to the temple where they tried to pray .There were 239 people on board the flight when it disappeared March 8, 2014 en route from Kuala Lumpur to Beijing. After one year and an exhaustive search, investigators still have no clue as to the whereabouts of the missing airliner. (Kevin Frayer/Getty Images)