Medics carry an injured at the explosion site in the busy center of Turkish capital, Ankara, Turkey, Sunday, March 13, 2016. The explosion is believed to have been caused by a car bomb that went off close to bus stops. News reports say the large explosion in the capital has caused several deaths and many casualties. (Photo by AP Photo)

A crocodile at a zoo in the southern Taiwan city of Kaohsiung holds the forearm of a zoo veterinarian in its teeth, April 2007. Surgeons in Taiwan have reattached a vet's arm, after it was bitten off by a crocodile as he tried to give it an anaesthetic injection. His attacker is one of a pair of Nile crocodiles kept at Shoushan zoo. Nile crocodiles are known to be man-eaters, but are also listed as an endangered species. (Photo by Frank Lin/Reuters)

People hold umbrellas as they walk past a flooded street in Taiyuan, Shanxi Province, China, July 19, 2016. (Photo by Reuters/China Daily)

Recruits who earned a place in the Motivation Platoon struggle through water and muck on their way to becoming a Marine or going into some other line of work, October 7, 1971. (Photo by Eddie Adams/AP Photo)

Lightning strikes near Jacobsdorf at the Oder-Spree district in eastern Germany, September 1, 2015. (Photo by Patrick Pleul/AFP Photo)

An Olympic Airways airplane stands on the premises of the former Athens International airport, Hellenikon June 16, 2014. For about six decades Hellenikon was Athens' only airport but it closed down in 2001 to make way for a newer, more modern airport before the city hosted the 2004 Olympic Games. After languishing for years as a wasteland of crumbling terminals, Hellenikon is set for resurrection as a glitzy coastal resort. Lamda Development, controlled by Greece's powerful Latsis family and leading a consortium of Chinese and Abu-Dhabi based companies, has big dreams for the area since signing a 915 million euro deal for a 99-year lease in March 2014. (Photo by Yorgos Karahalis/Reuters)

McMurdo Station is a U.S. Antarctic research centre located on the southern tip of Ross Island, which is in the New Zealand-claimed Ross Dependency on the shore of McMurdo Sound in Antarctica. It is operated by the United States through the United States Antarctic Program, a branch of the National Science Foundation. The station is the largest community in Antarctica, capable of supporting up to 1,258 residents, and serves as the United States Antarctic science facility. All personnel and cargo going to or coming from Amundsen–Scott South Pole Station first pass through McMurdo.

A woman looks out of a dusty window after boarding a bus to be transported to see the casket of Nelson Mandela at the Union Buildings in Pretoria, South Africa, Wednesday December 11, 2013. On Thursday, December 5, 2013, Mandela died at the age of 95. (Photo by Markus Schreiber/AP Photo)