John Gourley leans out of the cab of Goliath, one of Europe's largest cranes on September 20, 2011 in Rosyth, Scotland. The crane will begin the assembly of the Queen Elizabeth Class aircraft carriers later this week, when it lifts the first section of the two deck high 8,000 tonne centre block, which includes a section of the flight deck. The lift will mark the start of the Rosyth shipyards assembly of the first of two 65,000 tonne vessels the largest warships ever built for the Royal Navy. (Photo by Jeff J Mitchell/Getty Images)

St Louis County police officers arrest an anti-police demonstrator in Ferguson, Missouri August 10, 2015. Dozens of protesters were arrested on Monday afternoon after blocking rush-hour traffic on Interstate 70 a few miles (km) from Ferguson, Missouri, during demonstrations over the police shooting of an unarmed black man a year ago, according to a Reuters witness. (Photo by Lucas Jackson/Reuters)

Camel herders scoop up water in plastic buckets from one of the few watering holes in the area, to water their animals near the drought-affected village of Bandarero, near Moyale town on the Ethiopian border, in northern Kenya, Friday, March 3, 2017. The U.N. humanitarian chief, Stephen O'Brien, toured Bandarero village on Friday and called on the international community to act to “avert the very worst of the effects of drought and to avert a famine to make sure we don't go from what is deep suffering to a catastrophe”. (Photo by Ben Curtis/AP Photo)

Garrison Ireland Leigon member John O'Dwyer dressed as the character Darth Vader looks out towards Skellig Michael island on May 4, 2019 in Portmagee, Ireland. The latest Star Wars movies such as The Last Jedi have featured the famous Skellig Michael islands situated off the coast of the small Irish fishing village. The May the Fourth Star Wars festival is taking place in the small County Kerry village for the second year running as millions of fans worldwide celebrate the science fiction series. The quiet costal setting has seen a sharp rise in the number of tourists and fans visiting the area. (Photo by Charles McQuillan/Getty Images)

Boys pan for gold on a riverside at Iga Barriere, 25 km (15 miles) from Bunia, in the resource-rich Ituri region of eastern Congo February 16, 2009. Ituri is one of many areas of the country to have experienced bitter ethnic conflict between rival tribes in recent years. Massacres have left tens of thousands dead. It is this fighting that led U.S. authorities to take the unprecedented step of naming Congo in section 1502 of the Dodd-Frank financial regulation act, which says U.S.-listed companies that source gold, tungsten, tantalum and tin from Congo or its neighbours must assure the U.S. stock exchange regulator that their business is not helping fund conflict. (Photo by Finbarr O'Reilly/Reuters)

A man dressed up as the Statue of Liberty walks in front of a new digital advertising screen in Times Square, New York, November 18, 2014. According to local media the screen is a full block long, 8 stories tall, is lit with 24 million LED pixels and has a higher resolution than most TV sets. The advertising rate is reported at $2.5 million USD for a four-week run making it one of the most expensive outdoor advertising spaces in the world. (Photo by Carlo Allegri/Reuters)

A muddied family photograph sits on a hallway stairwell in an apartment block on March 17, 2011 in Kensennuma, Japan. Residents were allowed back to their homes today and began the massive cleanup operation caused by a 9.0 magnitude strong earthquake that struck on March 11 off the coast of north-eastern Japan. The quake triggered a tsunami wave of up to 10 metres which engulfed large parts of north-eastern Japan. The death toll has risen past 5000 with at least 8600 people still missing. (Photo by Chris McGrath/Getty Images)

British artist, Mark Coreth sits on top of the “Sydney Ice Bear” carved from a 10 tonne block of ice to illustrate how humans affect climate change in the Arctic at Customs House on June 3, 2011 in Sydney, Australia. The public will be welcomed to touch the bear, and leave an imprint which will begin the melting process and act as a metaphor for how humans affect the environment. The ice bear's has visited six cities on it's global tour since 2009; the visit to Sydney coincides with World Environment Day on June 5. (Photo by Lisa Maree Williams/Getty Images)