A People's Liberation Army (PLA) commando jumps through a fire hoop part of an exercise during an open day event at the Ngong Shuen Chau Barracks, the PLA navy base in the territory, in Hong Kong, China, 01 July 2015. Thousands of visitors attended the PLA open day yesterday and today to mark the 16th anniversary of the handover from British rule. (Photo by Jerome Favre/EPA)

National Guardsmen are put through riot training in Boston's Commonwealth Armory on Friday, October 18, 1974. Massachusetts Gov. Francis W. Sargent called up the guard to quell school violence, but the city has been relatively calm and the guard has remained in the armories. (Photo by JWG/AP Photo)

Ethnic Uyghur tourists guides wait to perform in a show for Chinese tourists on June 29, 2017 in the old town of Kashgar, in the far western Xinjiang province, China. Kashgar has long been considered the cultural heart of Xinjiang for the province's nearly 10 million Muslim Uyghurs. (Photo by Kevin Frayer/Getty Images)

A student, wearing a traditional costume and headdress, stands in line for interviews during a recruitment held by an airline company, hoping to stand out from more than 500 candidates for airline stewardess positions, in Chengdu, Sichuan Province, China, May 27, 2016. (Photo by Reuters/Stringer)

A general view of Hong Kong's business district is seen Thursday, August 1, 2013. (Photo by Vincent Yu/AP Photo)

Some of the worlds most iconic cities have been photographed as youve never seen them before in the shape of tiny round planets. By using a pioneering method of aerial photography, each location can be now seen at a full 360 degree angle. After some skilful manipulation on Photoshop known technically as stereographic projection, each sweeping panorama is then turned into a small circular shaped image. Whether its the Eiffel Tower, The Empire State Building or the Shanghai Skyline, each image manages to show hundreds of miles of city landscape. Here: the French Riveria of Cannes, France. (Photo by Airpano/Caters News)

Libyan leader Muammar Gaddafi attends the inauguration ceremony of Jacob Zuma on May 9, 2009 in Pretoria, South Africa. Jacob Gedleyihlekisa Zuma is South Africa's fourth President since the end of apartheid. (Photo by Foto24/Gallo Images/Getty Images)

A man walks through the morning mist in a park in Rozzano, near Milan, northern Italy, Thursday, December 17, 2015. (Photo by Antonio Calanni/AP Photo)