People pass a suitcase as they line up to enter a railway station in Beijing, February 15, 2015. Chinese Ministry of Transport said a total of 2.807 billion trips are expected to be made during the 40-day Spring Festival travel rush, which started on February 4 and will last until March 16, Xinhua News Agency reported. (Photo by Reuters/Stringer)

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 Egyptian army soldier stands guard near debris from a Russian airliner which crashed at the Hassana area in Arish city, north Egypt, November 1, 2015. Russia has grounded Airbus A321 jets flown by the Kogalymavia airline, Interfax news agency reported on Sunday, after one of its fleet crashed in Egypt's Sinai Peninsula, killing all 224 people on board. (Photo by Mohamed Abd El Ghany/Reuters)

A Syrian boy is comforted as he cries next to the body of a relative who died in a reported airstrike on April 27, 2016 in the rebel-held neighbourhood of al-Soukour in the northern city of Aleppo. The Syrian army was preparing an offensive to retake the whole of Aleppo, as fighting in the divided second city killed 38 civilians in a new blow for a tattered truce. Nearly 200 people have been killed in Aleppo in the past week as rebels have pounded government-held neighbourhoods with rocket and artillery fire and the regime has hit rebel areas with air raids. (Photo by Karam Al-Masri/AFP Photo)

A sick California sea lion with possible domoic acid poisoning is rescued to be evaluated by volunteers from CIMWI (Channel Islands Marine & Wildlife Institute) in Santa Barbara, California, on March 25, 2025. Over a hundred sea lions, dolphins and other marine mammals, including birds, have been sickened by domoic acid poisoning from algal blooms in Southern California since February, US media reported. (Photo by David Swanson/AFP Photo)

People walk through crop circles in a cornfield near Raisting, Germany, on July 28, 2014. According to media reports, a balloonist had discovered the circle some days ago. Since then, hundreds of people came to the field to watch it, however it is unclear who did create the pattern. (Photo by Karl-Josef Hildenbrand/DPA)

A visiter is attracted by the chairs covered with solar panels at the factory of Yingli Green Energy Holding Company, also known as Yingli Solar, on June 20, 2011 in Baoding city of Hebei Province, China. According to a report by the International Energy Agency (IEA), China overtook America as the world' s largest energy consumer in 2010. New energy industries are becoming even more important than in the past. (Photo by Feng Li/Getty Images)

A Manipuri woman sells smoked and dry fish in Ima market - the world's largest all women market – in Imphal city, Manipur state, 06 January 2016. The 150-year-old Ima Keithel or “Mothers's market” complex, which is run exclusively by women and was damaged in the 04 January 2016 earthquake, is returning back to normal. Nine deaths have been reported from in and around Imphal due to falling debris. Imphal has a population of some 270,000 and people were jolted from their sleep and ran out of their homes in panic when the earth shook 04 January, reports say. (Photo by EPA/Stringer)