Israeli soldiers play the parts of wounded civilians during a drill simulating a toxic spill from an attack on a train in Beersheba, southern Israel, 13 January 2016, as Home Front medical teams, fire fighters and police carry out rescue operations. The large scale drill is the concluding exercise of the Fourth International Conference on Healthcare System Preparedness and Response to Emergencies and Disasters and includes some 200 of the world's experts on health system readiness from around the world. The conference is dealing with all types of medical emergencies from terrorist attacks to natural disasters. (Photo by Jim Hollander/EPA)

These breathtaking images capture the hidden depths of one of the worlds largest caves, which is so big its home to a beach, a river and a jungle. At more than 130m high, and 150m across, the imposing cave is so big as high as the London Eye and wider than one-and-a-half football pitches. Here: The campers set up inside the cave on the beach. (Photo by Lars Krux/Caters News)

Mrs. Marie Graskamp of Milwaukee shows the different positions one might assume when entering the bomb shelter in Milwaukee September 3, 1958. This circular entrance is about three feet in diameter. This is the entrance (according to the builders) that would connect to the cellar of a home assuming the shelter was in the ground for added protection. If a bombing should occur, all members of family would proceed to the cellar and then through the circular port into the shelter. (Photo by AP Photo)

Clowns Perlita and Tapetito, wearing protective gear amid the new coronavirus pandemic, speak with resident Enrique Zeballos as they arrive to disinfect his home free of charge, in El Alto, Bolivia, Friday, September 11, 2020. The lack of traditional employment for the clowns due to the pandemic has led them towards other avenues of making money. But for people with limited income they provide their disinfection services free of charge. (Photo by Juan Karita/AP Photo)

A staff member of a toy store wears a face mask as she invites customers to enter the store, in London, Tuesday, September 22, 2020. British Prime Minister Boris Johnson has slammed the brakes on the country's return to offices, saying people should work from home if possible to help slow the spread of the coronavirus. Johnson on Tuesday announced a package of new restrictions, including a requirement for pubs, restaurants and other hospitality venues in England to close between 10 p.m. and 5 a.m. (Photo by Frank Augstein/AP Photo)

Miranda state beauty pageant contestant Luiseth Materan, wearing a protective face mask issued by the Miss Venezuela beauty pageant, arrives to the Venevision television station to prepare for a meeting with judges, in Caracas, Venezuela, Friday, September 18, 2020. Quarantine rules and social distancing has forced the contestants to train at home and online with limited access to the venue itself where strict measures are in place. The pageant is due to take place on Sept. 24. (Photo by Ariana Cubillos/AP Photo)

Residents display scarecrows with an NHS theme outside their homes in Greenfield for the annual scarecrow parade on April 09, 2020 in Manchester, United Kingdom. There have been around 60,000 reported cases of the COVID-19 coronavirus in the United Kingdom and 7,000 deaths. The country is in its third week of lockdown measures aimed at slowing the spread of the virus. (Photo by Anthony Devlin/Getty Images)

People react as the body of a relative is retrieved from the ruin of a building at an area affected by an earthquake in Mamuju, West Sulawesi, Indonesia, Friday, January 15, 2021. A strong, shallow earthquake shook Indonesia's Sulawesi island just after midnight Friday, toppling homes and buildings, triggering landslides and killing a number of people. (Photo by Yusuf Wahil/AP Photo)