Belly dancer Nagwa Fouad sailing on the river Nile, 1972. Egypt is one of 23 countries represented at the Dubai Photo Exhibition, showing off photography that dates to the 1920s. Dubai Photo Exhibition is in various venues of Dubai’s design district from 16-19 March. (Photo by Farouk Ibrahim)

“Slow”. A calm cow in the messy streets of Jodhpur. Photo location: India. (Photo and caption by Matthias Troeger/National Geographic Photo Contest)

Zhang Ze of China in action during his Oceania zone group1 match against Bernard Tomic of Australia of the 2011 Davis Cup on July 8, 2011 in Beijing, China. (Photo by Lintao Zhang/Getty Images)

British soldiers inspect a captured German place in the Horseguards' Parade, London during World War I in November 1914, with the London Eye in the background as a reminder of just how much has changed in the last 100 years. (Photo by Peter Macdiarmid/Getty Images)

Photographers take photographs of the Large Air Tanker (LAT) C-130 Hercules, also known as “Thor”, as it drops a load of around 15,000 litres during a display by the Rural Fire Service ahead of the bushfire season at RAAF Base Richmond Sydney, Australia, September 1, 2017. (Photo by David Gray/Reuters)

A group of youngsters dressed as ghouls and zombies for Halloween parade in downtown Lisbon, Portugal, Friday, October 31, 2014. (Photo by Francisco Seco/AP Photo)

British-based Ukrainians gather outside the Russian Embassy in London to protest against the build-up of troops in the Crimea region, on March 2, 2014. The demonstrators chanted and held banners demanding “Hands off Ukraine”. (Photo by John Stillwell/PA Wire)