A swimmer competes in Le Defi Monte-Cristo (Monte Cristo Challenge) swimming event at the Chateau d'If, off the coast of Marseille, southern France, on June 21, 2019. Created in 1999 and inspired by Alexandre Dumas' character of Edmond Dantes, the Monte Cristo Challenge will take place from June 21 to 23, 2019. (Photo by Boris Horvat/AFP Photo)

A man walks by as tourists take selfies on the French Riviera city of Nice on June 24, 2019, as temperatures soar to 33 degrees Celsius. Forecasters say Europeans will feel sizzling heat this week with temperatures soaring as high as 40 degrees Celsius (104 degrees Fahrenheit) in an “unprecedented” June heatwave hitting much of Western Europe. (Photo by Valery Hache/AFP Photo)

Dario Sammartino, of Italy, competes at the final table during the World Series of Poker at the Rio hotel-casino in Las Vegas Sunday, July 14, 2019. (Photo by Steve Marcus/Las Vegas Sun via AP Photo)

An Extinction Rebellion environmental activist couple getting married at an action site they are calling “The Beacon” on Westminster Bridge on October 7, 2019 in London, England. Primarily made up of London based activists the site is one of 12 situated around key Government locations in central London as actions are also predicted to occur in unto 70 cities around the world. The group aim to occupy the areas in central London for up to two weeks through non violent protest with an estimated 8 times as many people as their April protests which saw over 1,200 people arrested. (Photo by Ollie Millington/Getty Images)

The pedestrian zone on the banks of the “Parco della Pace” at Lake Maggiore is flooded due to flooding, on Thursday, October 24, 2019 in Locarno, Switzerland. (Photo by Samuel Golay/Ti-Press/Keystoen)

A participant in the Borodino Battle re-enactment before the show at the Borodino Field in the Moscow Region on September 4, 2016. The Battle of Borodino, fought on September 7, 1812, was a battle fought in the Napoleonic Wars during the French invasion of Russia. The fighting involved around 250,000 troops and left at least 70,000 casualties, making Borodino the deadliest day of the Napoleonic Wars. (Photo by Kirill Kallinikov/Sputnik)

In this November 12, 2015, file photo, Mt. Everest is seen from the way to Kalapatthar in Nepal. An American climber has died near the summit of Mount Everest and an Indian climber is missing after heading down from the mountain following a successful ascent, expedition organizers said Sunday. (Photo by Tashi Sherpa/AP Photo)

Katie Rose Hobbs and Kirsten Elizabeth Pobjoy of British Aerosuperbatics Wingwalking Team perform ballet in the air during Huangguoshu Waterfalls Flight Conference on August 3, 2018 in Anshun, Guizhou Province of China. Huangguoshu Waterfalls Flight Conference including 18 aircraft from seven aerobatic teams from all over the world kicked off on Friday. (Photo by VCG via Getty Images)