Swiss police officers stand beside of mock gates of the NEAT Gotthard Base Tunnel inside the event hall for the upcoming opening ceremony near the town of Erstfeld, Switzerland May 31, 2016. The celebrations of the opening of the Gotthard Base Tunnel will start on June 1, 2016. With a length of 57 km (35 miles) crossing the Alps, the Gotthard Base tunnel is the world's longest train tunnel. (Photo by Arnd Wiegmann/Reuters)

Singer Katy Perry arrives at the Metropolitan Museum of Art Costume Institute Gala 2015 celebrating the opening of “China: Through the Looking Glass” in Manhattan, New York May 4, 2015. (Photo by Lucas Jackson/Reuters)

Young girls dress up in traditional costumes and pose for a selfie at the opening ceremony of the Leishan Miao new year festival in the city of Kaili, Guizhou province, China on November 23, 2015. (Photo by Imaginechina/Rex Shutterstock)

An Emperor Tamarin monkey, native to the Amazon rainforest, experiences its new home in the living rainforest enclosure at ZSL London Zoo on March 25, 2010 in London, England. Entitled “Rainforest Life” the large temperature and humidity controlled bio-dome is home to free-roaming monkeys, sloths, tree anteaters and tropical birds. The exhibit, which is opening in the International Year of Biodiversity, will be open to the public from March 27, 2010. (Photo by Oli Scarff/Getty Images)

A model presents a creation at a metro station during a show opening the Moscow Fashion Week in Moscow, Russia on October 22, 2019. (Photo by Evgenia Novozhenina/Reuters)

Kim Kardashian arrives for the Thierry Mugler exhibition opening at the Montreal Museum of Fine Arts in Montreal, Chittenango, United States of America on February 26, 2019. (Photo by Splash News and Pictures)

Attendee Ana Niebla arrives in costume as Princess Penny Wise for opening night of the pop culture festival Comic Con International in San Diego, California, U.S., July 17, 2019. (Photo by Mike Blake/Reuters)

French aircrafts of the Patrouille de France spray colored smoke during a performance on the opening day of the Dubai Airshow in Dubai, United Arab Emirates, Sunday, November 17, 2019. (Photo by Kamran Jebreili/AP Photo)