Emergency services work at the scene of a bus accident on the Kingsway in central London February 2, 2015. A number 91 double-decker bus had its roof ripped off after hitting a tree, causing injury to passengers and passers-by, local media reported. (Photo by Peter Nicholls/Reuters)

New York Police Department tactical police officers stand guard near the New York Stock Exchange on September 9, 2011 in New York City. Officials are stepping up security in New York and Washington D.C. a day after U.S. officials received a credible but unconfirmed terror threat to utilize car bombs on bridges or tunnels in New York or Washington. (Photo by Justin Sullivan/Getty Images)

The Glastonbury Grace Cup, a rare carved oak tankard is and an 18th century replica in silver gilt (L), is held at Glastonbury Abbey for the first time in 125 years on December 12, 2011 in Glastonbury, England. (Photo by Matt Cardy/Getty Images)

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)

A child watching the sea while residents try to clear the bed of a river that has been blocked by debris left by Hurricane Matthew, in the commune of Roche-a-Bateaux, in the south west of Haiti, on October 21, 2016. At least 546 people were killed and more than 175,000 people lost their homes when Hurricane Matthew roared ashore on October 4, packing winds of 145 miles (230 kilometers) per hour. (Photo by Hector Retamal/AFP Photo)

A soldier beaten by the mob (C) is protected by plain chothes policemen after troops involved in the coup surrendered on the Bosphorus Bridge in Istanbul, Turkey July 16, 2016. (Photo by Murad Sezer/Reuters)

Shipping containers sit idle at the ports of Los Angeles and Long Beach, California in this aerial photo taken February 6, 2015. The loading and unloading of cargo freighters has been suspended at all 29 U.S. West Coast ports this weekend because of chronic slowdowns on the docks that shippers and terminal operators have blamed on the dockworkers' union, the companies said Friday. (Photo by Bob Riha, Jr./Reuters)