An injured young woman is led away after an incident at Parsons Green underground tube station in west London on September 15, 2017. Police and ambulance services said they were responding to an “incident” at Parsons Green underground station in west London on Friday, following media reports of an explosion. A Metro. co. uk reporter at the scene was quoted by the paper as saying that a white container exploded on the train and passengers had suffered facial burns. (Photo by Luke MacGregor/Reuters)

Mercury and Maia, fueled and overhauled, are waiting in the Tay at Dundee, for favorable weather to start the flight to the Cape, a distance of 6,370 miles. The composite machine moored in the Tay River, at Dundee, on September 23, 1938. (Photo by AP Photo)

South Vietnamese-born designer Quasar drives the six-foot long square-shaped plastic car he built and which is scheduled to be a hit with the young driving set, in Paris, June 23, 1967. The car can be driven at speeds of up to 60 mph (Photo by Michel Laurent/AP Photo)

“Be prepared” is the motto of petite Doris Sherrell, vocalist and dancer with “Blackouts of 1942”. In the event of a bombing, the young lady had her social security number tattooed on one leg by artist Jack Julian, and address placed on the other limb for means of identification in Los Angeles, September 29, 1942. (Photo by AP Photo)

Belarusian schoolchildren, who are members of a pro-government Young Pioneer movement, perform with drums as they take part in a meeting to mark the 95th anniversary of their organisation in Minsk, Belarus May 19, 2017. (Photo by Vasily Fedosenko/Reuters)

School teachers and staff members take part during an active shooter training at James I. O'Neill High School in Highland Falls, New York, U.S., December 12, 2017. (Photo by Eduardo Munoz/Reuters)

Five-month-old baby elephant Fah Jam swims during a hydrotherapy treatment as part of a lengthy rehabilitation process to heal her injured front left foot at a rehabilitation center in Pattaya, Thailand January 5, 2017. The baby elephant was injured at three months old when she got stuck in an animal snare put up by villagers to prevent elephant intrusions in Chanthaburi province. (Photo by Athit Perawongmetha/Reuters)

A person enter in sauna on the peak of Mount Lagazuoi in Cortina D'Ampezzo, Italy January 16, 2018. Picture taken January 16, 2017. (Photo by Stefano Rellandini/Reuters)