A baby Black-crowned Night Heron squawks in its incubator while being cared for at City Wildlife rescue and rehabilitation center in Washington, DC on May 31, 2017. The heron is one of several that have been brought to CW by the staff at The National Zoo over the past few years. (Photo Linda Davidson/The Washington Post)

Police officers take cover as they clash with protesters after an officer shot and killed a black man in Brooklyn Center, Minneapolis, Minnesota on April 11,2021. Protests broke out April 11, 2021 night after US police fatally shot a young Black man in a suburb of Minneapolis – where a former police officer is currently on trial for the murder of George Floyd. Hundreds of people gathered outside the police station in Brooklyn Center, northwest of Minneapolis. Police fired teargas and flash bangs at the demonstrators, according to an AFP videojournalist at the scene. (Photo by Kerem Yucel/AFP Photo)

A girl holds her brother in her arm as black smoke rises after an oil well set on fire in the center of al-Kayyara town to the south of Daesh terror organization-held Mosul in Iraq on October 25, 2016. The oil well in the center of al-Kayyara town, which was set alight by retreating Daesh militants in advance of the Iraqi army's takeover of the town on August 24, 2016 has still not entirely been put out. The raw petrol which is still alight is creating black clouds above the city. The residents and wildlife beneath this polluting smoke cloud may find their health at risk. The effects of the fire in the town center on unprotected civilians' health can easily be seen on the hands and faces of children playing on the street. (Photo by dris Okuducu/Anadolu Agency/Getty Images)

A demonstrator uses a TV case as a facemask during a protest to demand justice for Daniel Prude, on September 3, 2020 in New York City. Protests were planned in New York September 3 over the death of Daniel Prude, a black man that police hooded and forced face down on the road, according to video footage that prompted a probe from the state's attorney general. (Photo by Kena Betancur/AFP Photo)

Hurricanes player Xavier Numia and Black Ferns player Marcelle Parkes train in isolation at Polo Ground Park due to the coronavirus lockdown on May 06, 2020 in Wellington, New Zealand. New Zealand has been in lockdown since Thursday 26 March following tough restrictions imposed by the government to stop the spread of COVID-19 across the country. (Photo by Hagen Hopkins/Getty Images)

A woman cries as she watches a building burn after a protest over the death of George Floyd, Sunday, May 31, 2020, in La Mesa, Calif. Protests were held in U.S. cities over the death of Floyd, a black man who died after being restrained by Minneapolis police officers on May 25. (Photo by Gregory Bull/AP Photo)

Black Live Matter march from Clapham Common (led by Iman, the Forever Family Force and the Slow Boys, on motorbikes) to join the Stop the Maangamizi: Afrikan Emancipation Day Reparations Rebellion in London, UK on August 1, 2020. They aim to lock-down Brixton because “WE/they are not being HEARD” in their demand for the UK Government to establish the All-Party Parliamentary Commission of Inquiry for Truth & Reparatory Justice. (Photo by Guy Bell/Alamy Live News)

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)