A Sotheby's employee holds a rare 52.82-carat white diamond ring at Sotheby's auction house on April 12, 2010 in London, England. Price: 7 million USD. (Photo by Dan Kitwood/Getty Images)

A woman walks with her baby past a PM militarized police soldier in position and aiming his rifle in Rocinha favela in Rio de Janeiro, Brazil on September 23, 2017. Although shooting was reported in the early hours of Saturday in Rocinha – for the seventh day running – officials said that Friday's deployment of 950 soldiers to reinforce police had brought the crisis under control. (Photo by Carl De Souza/AFP Photo)

The Eiffel Tour-the body language of balance. I came across this group of young adults from Sarajevo, Bosnia, having fun testing their balance two nights ago in on the Esplanade de Trocadero. (Photo and comment by Peter Turnley)

Li Yuming, a local farmer who is interested in scientific invention, works on his unfinished miniature submarine “Xiaguang V” on the outskirts of Wuhan, capital of central China's Hubei province August 24, 2007. “Xiaguang V”, which is 3-metre long, 1.2-metre in height, has a maximum diving depth of 20 metres, and can hold two adults and one child at the same time. The submarine will be used for tour after safety test, local media said. (Photo by Reuters/Stringer)

People watch police destroy confiscated illegal firecrackers in Shenyang, Liaoning province, China, January 29, 2016. (Photo by Reuters/Stringer)

Heidi Klum (not pictured) was greeted by half-naked models arriving at Myer Melbourne on January 27, 2016 in Melbourne, Australia. The supermodel continued her tour of the country promoting her new season of lingerie for Heidi Klum intimates, a brand which she took over from Elle Macpherson in 2014. (Photo by Robert Cianflone/Getty Images)

Back in England, one of the British soldiers that continue to return in their thousands from Northern France, belies any mood of defeat with some high spirited piping on a train. (Photo by Parker/Fox Photos/Getty Images). 1st June 1940

The first load of passengers queuing for the Bennie Railplane in Glasgow; the inventor George Bennie is third in the queue. The streamlined cars are self propelled, driven by air screws in front and behind, and hang from a steel girder. (Photo by J. A. Hampton/Topical Press Agency/Getty Images). 4th July 1930