Workers lay railway track in a tunnel of the Crossrail project in Stepney, east London, Britain, November 16, 2016. Crossrail, which is Europe's largest construction project, is a railway link which will connect outlying areas to the east and west of London with tunnels under the centre of the capital. (Photo by Stefan Wermuth/Reuters)

On September 1, 2004, Chechen militants stormed an elementary school in the town of Beslan in the Russian republic of North Ossetia. They took 1,100 teachers, children, and their relatives hostage, demanding the withdrawal of federal forces from Chechnya as a condition for their release. On September 3, 2004, Russian security forces stormed the building, resulting in a battle in which more than 330 hostages died, including 186 children. Here: A man assists two young hostages who managed to escape from the school building after special forces entered the school in Beslan, North Ossetia, Friday 03 September 2004. (Photo by Yuri Kochetkov/EPA)

A young visitor interacts with a baby hippopotamus swimming in its enclosure at the Berlin Zoo on January 1, 2018. Tourists and locals flocked to the zoo in the German capital on the unseasonably warm first day of the year. (Photo by Odd Andersen/AFP Photo)

This picture taken on January 6, 2018 shows macaque monkeys looking at a man's camera during snowfall at Wulongkou Nature Reserve in Jiyuan in China's central Henan province. (Photo by AFP Photo/China Stringer Network)

A woman wearing a protective mask is seen behind a girl dressed in a Plague Doctor Mask in Western-Ukrainian city of Lviv, Ukraine, 22 March 2020. Ukrainian Designer Anastasia Markovska sewed protective masks looking like Plague Doctor Masks, the traditional costume of Venice Carnival, for herself and her friends due to the ongoing pandemic of the COVID-19 disease caused by the SARS-CoV-2 coronavirus. In Ukraine had been 47 laboratory-confirmed cases of COVID-19, including three deaths and one recovery as Ukraine's Health Ministry announced. (Photo by Pavlo Palamarchuk/EPA/EFE)

Young children at a Bristol, Great Britain health centre unsure of the benefits of sun-lamps and the special glasses that must be worn, July 1948. The health centre was part of the newly introduced free National Health Service. (Photo by Popperfoto/Getty Images)

A demonstrator sits on the coffin containing the body of a protester who was killed during previous protests in Port-au-Prince, Haiti, Monday, March 4, 2019. Protesters are angry about skyrocketing inflation and the government's failure to prosecute embezzlement from a multi-billion Venezuelan program that sent discounted oil to Haiti. (Photo by Dieu Nalio Chery/AP Photo)

Nature, singles winner: Frogs with their legs severed struggle to the surface, surrounded by frogspawn, after being thrown back into the water in Covasna, Romania. (Photo by Bence Mate/World Press Photo 2019)