Handout photo issued by Easyart of an experimental motorcycle as an archive of weird and wacky innovations has been unearthed by an amateur historian as he trawled through a collection of images spanning the last 100 years. (Photo by Easyart/PA Wire)

Boys eat at a rubbish dump where they are collecting recyclable waste outside Yemen's Red Sea port city of Houdieda January 20, 2016. (Photo by Abduljabbar Zeyad/Reuters)

South Korea's Black Eagles aerobatics team performs an aerial display forming a Ying and Yang logo during the Singapore Airshow at Changi exhibition center in Singapore on February 16, 2016. (Photo by Roslan Rahman/AFP Photo)

Pilot Akmal Bin Abdul Kahar watches South Korea's Black Eagles aerobatics team perform a manoeuvre during an aerial display at the Singapore Airshow at Changi Exhibition Center February 18, 2016. (Photo by Edgar Su/Reuters)

Crowds look on as Xolo the Giant Dog, one of the giant Royal De Luxe street puppets taking part in Liverpool's World War I centenary commemorations, walks through the streets of Liverpool on July 25, 2014 in Liverpool, England. French street theatre company Royal de Luxe are putting on a show throughout the city as part of Liverpool's World War I centenary commemorations from July 23-27. The giant puppet grandmother has slept in the hall for two days as part of “Memories of August 1914”. As the giants tour the city the Little Girl Giant and her dog Xolo will meet up with the giant Grandmother telling the story of life leading up to World War One. (Photo by Christopher Furlong/Getty Images)

LONDON - JUNE 04: A piece entitled “Entrance into wood” by Elke Krystufek goes on show at The Royal Academy Summer Exhibition on June 4, 2008 in London. In it's 240th year, the exhibition displays a wide range of recent work by both established and emerging artists. 10,000 artists submitted work for selection this year. (Photo by Peter Macdiarmid/Getty Images)

Egyptian bootblacks cleaning a European's shoes in Cairo. (Photo by Hulton Archive/Getty Images). Circa 1870

A four-year-old bulldog named Goldie wearing spectacles and a nightcap. (Photo by Fox Photos/Getty Images). 9th January 1960