General Maurice Gamelin, General Officer commanding the French Armies, is on a four day visit to England. He went to the staff college at Minley and is seen inspecting an anti-tank gun at Aldershot, on June 7, 1939. (Photo by AP Photo)

On the second straight day of record-setting temperatures, Maddy Hacker is hoisted up by friend Jasmine Harper, both of McLean, Virgnia, as they attempt an acrobatic stunt in front of the U.S. Capitol in Washington, U.S., February 21, 2018. (Photo by Kevin Lamarque/Reuters)

Strokkur geyser against cloudy sky at sunset. Strokkur is a fountain geyser located in a geothermal area beside the Hvítá River in Iceland in the southwest part of the country, east of Reykjavík. It is one of Iceland's most famous geysers, erupting once every 6–10 minutes. Its usual height is 15–20 m, although it can sometimes erupt up to 40 m high. (Photo by Teatsche Dijkhuis/Getty Images/EyeEm)

The Thufa hill in Reykjavik, Friday, October 28, 2016. Parliamentary elections will be held in Iceland on October 29, 2016, more than 250,000 voters are called to elect the new parliament, 63 members of the Althing parliament. (Photo by Frank Augstein/AP Photo)

German-American model and television personality Heidi Klum is seen on February 19, 2019 in Los Angeles, California. (Photo by BG002/Bauer-Griffin/GC Images)

Shaymaa Ismaa’eel, a 24-year-old Muslim woman passes by a group of angry protesters at an Islamic conference in Washington, DC on April 21, 2019. In response, she crouched in front of them and flashed a peace sign. The photo, posted on Instagram, prompted an outpouring of support. (Photo by Shaymaa Ismaa'eel/Instagram)

An Indigenous schoolchild dressed in traditional attire takes part in a rally to commemorate Indigenous Resistance Day in Catarina town, Nicaragua October 12, 2016. This holiday coincides with Columbus Day which commemorates Christopher Columbus landing in America in 1492. But rather than celebrating the discovery of the Americas, the Nicaraguans observe Indigenous Resistance Day to celebrate the bravery of the indigenous population in the fight against the Spanish conquistadors. (Photo by Oswaldo Rivas/Reuters)

Roof-topping enthusiast Daniel Lau takes a selfie with high-rise buildings down below as he stands on the top of a skyscraper in Hong Kong, China on August 15, 2017. A craze that began in Russia has now taken hold in Hong Kong, one of the world's most vertical cities. Mr Lau said he had been inspired by Russian climbers and that he was unafraid of the vertiginous heights he scales. (Photo by ImagineChina/Rex Features/Shutterstock)