A United States Air Force (USAF) F-15 fighter jet travels at low altitude through the “Mach Loop” series of valleys near Dolgellau, north Wales on June 26, 2018. The Mach Loop valleys, situated between Dolgellau and Machynlleth, are regularly used by the military for operational low flying training which can take place as low as 76 metres from the nearest terrain. The USAF regularly use the loop to practice low-altitude flight, which confuses radar systems. (Photo by Oli Scarff/AFP Photo)

This aerial picture taken on June 6, 2016, shows the scene of a collision between a freight train and a passengers train on their way between Liege and Namur, in Saint-Georges-sur-Meuse, Eastern Belgium. Investigators worked through the wreckage of a high speed train crash in eastern Belgium on Monday that killed at least three people and injured nine others. A fast-moving passenger train late Sunday slammed violently into the back of a slow-moving freight train that was travelling on the same track for reasons that remain unexplained. (Photo by Laurie Dieffembacq/AFP Photo)

Ellen MacRae a student from Edinburgh University take a lateral flow antigen test at a test centre which is also open to students in Edinburgh Napier University, Queen Margaret University and SRUC on December 1, 2020 in Edinburgh, Scotland. The programme is running in partnership between the University of Edinburgh and other Scottish universities, the Scottish Government and NHS Test and Protect, supporting students leaving their term-time accommodation to travel home at the end of term for the winter break. (Photo by Jeff J. Mitchell/Getty Images)

Men wear masks as they sit in the metro in Prague, Czech Republic, 17 March 2020. According to media reports, the Czech government decided to impose a two-week quarantine in the country on the evening of 15 March, and ban all international travel from 16 March 2020. Currently 383 cases of the coronavirus SARS-CoV-2, which causes the Covid-19 disease, have been officially confirmed in Czech Republic. (Photo by Martin Divisek/EPA/EFE)

This aerial photo shows bullet trains parked at a station in preparation for the upcoming Lunar New Year travel peak in Nanjing, in eastern China's Jiangsu province on January 27, 2021, as authorities have encouraged people to stay put during the Spring Festival to curb the spread of of COVID-19 coronavirus. (Photo by AFP Photo/China Stringer Network)

A man uses a snow blower to clear a sidewalk during a winter storm ahead of the Christmas Holiday outside the Union Station, in Chicago on December 22, 2022. More than 2,200 flights were canceled across the United States by Thursday afternoon as a massive winter storm named Elliot upended holiday travel plans with a triple threat of heavy snow, howling winds and bitter cold (Photo by Kamil Krzaczynski/AFP Photo)

Cheetah Darcy enjoys her newly-developed Cheetah Territory that covers 10,000 square at Yorkshire Wildlife Park, near Doncaster, UK on Wednesday, August 16, 2023. Darcy, who is four-years-old, travelled from Ireland's Fota Wildlife Park to YWP last week where she will be joined by 13-year-old male Brooke who is on his way from the Bristol Zoo Project as a recommendation by the European Endangered Species Programme. (Photo by Danny Lawson/PA Images via Getty Images)

In this picture taken on September 5, 2023, students practice contortionism at the Flower Studio in Ulaanbaatar. Mongolian circus performers fly through the air of a cavernous hall inspectors have warned could collapse at any time, one of the few places left to train if they hope to travel the world with their country's spectacular big top shows. (Photo by Pedro Pardo/AFP Photo)