Employee Jenny Forgie works on an orchid display at Kew Gardens in London, Thursday, February 8, 2018. The 23rd annual Orchid Festival is the first one with a Thailand theme, 66 volunteers worked on the 6,950 exhibited orchids. The festival is open from Feb. 10, 2018 until March 11, 2018. (Photo by Frank Augstein/AP Photo)

A young woman holds her smartphone at Red Square with the Kremlin's Spasskaya Tower, right, and St. Basil Cathedral, center, in the background in Moscow, Russia, Monday, July 25, 2016. (Photo by Pavel Golovkin/AP Photo)

Ratana Das, 40, a female vendor, carries sacks full of clothes at a second-hand clothing market early morning in Kolkata, India, March 10, 2016. Das said she was born and brought up in Kolkata and feels proud being a resident of the city that gives her he opportunity to be financially independent. (Photo by Rupak De Chowdhuri/Reuters)

Syrian Internal Security Forces dance in celebration during their graduation ceremony, at Ain Issa desert base, in Raqqa province, northeast Syria, Thursday, July 20, 2017. Some 250 residents of Syria's Raqqa province are the latest batch to graduate from a brief U.S-training course that is preparing an internal security force to hold and secure areas as they are captured from Islamic State militants. (Photo by Hussein Malla/AP Photo)

A worker cleans the statue of Yuri Gagarin, the first person who flew to space, ahead of Cosmonautics Day celebrated on April 12, in Moscow, Russia, Wednesday April 10, 2019. Cosmonautics Day marks when Soviet cosmonaut Yuri Gagarin became the first man to fly in space, in 1961, orbiting the earth once before making a safe landing. (Photo by Maxim Marmur/AP Photo)

A runner competes in the Great Wall Marathon at the Huangyaguan Great Wall outside Beijing, China, May 18, 2019. (Photo by Thomas Peter/Reuters)

Union Berlin players celebrate after the Bundesliga playoff second leg match between 1. FC Union Berlin and VfB Stuttgart at Stadion an der alten Foersterei on May 27, 2019 in Berlin, Germany. (Photo by Annegret Hilse/Reuters)

The Jet Propulsion Lab team's RoboSimian robot turns on a valve at a simulated disaster-response course during day one of the Defense Advanced Research Projects Agency (DARPA) Robotics Challenge finals in Pomona, California, June 5, 2015. (Photo by David McNew/Reuters)