Gremio fans celebrate after their team won the Copa Libertadores final match at the Arena do Gremio in Porto Alegre, Brazil on November 29, 2017. (Photo by Diego Vara/Reuters)

The giant metal structure sits 330ft above the ground on the roof of a 22 storey office block in Dutch capital Amsterdam on September 6, 2016. Tourists sit in a playground-style chair as they propel themselves them over the edge of the building with only thin-air between them and the ground below. Engineers spent several years designing and building the breathtaking swing. By being fixed to the top of a building it reaches new heights – dwarfing other swings around Europe but trailing behind the 1,150ft high mechanical rides at the Stratosphere Hotel in Las Vegas, Nevada. (Photo by Huub Zeeman/SWNS.com)

Prince Charles, Prince of Wales (R) and Camilla, Duchess of Cornwall (L) visit Seppeltsfield Winery in Barossa Valley, Australia, 10 November 2015. The royal couple are on a 12-day tour visiting seven regions in New Zealand and three states and one territory in Australia. (Photo by Daniel Kalisz/EPA)

A polar bear fast asleep at London Zoo. (Photo by Fox Photos/Getty Images). 1961

A steam traction engine with a broken rear axle in Pall Mall, London. (Photo by Topical Press Agency/Getty Images). November 1923

Children carrying guns and flags or wearing Soviet-style uniforms have become a common sight at Victory Day parades and other events in Russian-controlled Crimea. Russian and Ukrainian human rights activists have warned that such displays point to a growing trend of promoting Russian patriotism among kids on the Crimean peninsula, annexed from Ukraine in 2014. Here: A young Crimean girl wears military-type clothes during a Victory Day celebration in Sevastopol on May 9, 2018. (Photo by Oleksandra Surgan/Radio Free Europe/Radio Liberty)

Soap Bubble Structures by Kym Cox. Bubbles optimise space and minimise their surface area for a given volume of air. This phenomenon makes them a useful tool in many areas of research, in particular, materials science and “packing” – how things fit together. Bubble walls drain under gravity, thin at the top, thick at the bottom, which interferes with travelling lightwaves to create bands of colour. Black spots show the wall is too thin for interference colours, indicating the bubble is about to burst. (Photo by Kym Cox/2019 Science Photographer of the Year/RPS)

This 2014 series Shanghai Tian Wa saw Chinese photographer Liu Tao train his lens on two distinct districts in Shanghai. Here: “Shanghai Tian Wai №26, 2014”. (Photo by Liu Tao/The Guardian)