A woman looks out of a dusty window after boarding a bus to be transported to see the casket of Nelson Mandela at the Union Buildings in Pretoria, South Africa, Wednesday December 11, 2013. On Thursday, December 5, 2013, Mandela died at the age of 95. (Photo by Markus Schreiber/AP Photo)

Sport category, winner: Yuan Peng. Liu Bingqing and Liu Yujie are twin sisters who have studied and trained in gymnastics since their early childhood in Jining, China. (Photo by Yuan Peng/Sony World Photography Awards)

The winners of the Historic Photographer of the Year Awards 2020 from triphistoric.com celebrate the places and cultural sites around the world that offer a window to the history that exists all around us. This year, restricted by Covid, photographers were called on to scour their photographic archive to share their imagery of those places that dominate our past. Here: The Brighton Palace Pier. (Photo by Michael Marsh/Historic Photographer of the Year 2020)

Dawn at Blyth beach huts in Northumberland, with the prospect of warm weather over the coming weekend on Friday, October 8, 2021. (Photo by Owen Humphreys/PA Images via Getty Images)

Right wing demonstrators chase a Black Lives Matter protester after a pro-Trump caravan rally convened at the Oregon State Capitol building on September 7, 2020 in Salem, Oregon. The caravan event, billed as the Oregon For Trump 2020 Labor Day Cruise Rally, began in Clackamas and made its way to the Oregon State Capitol in Salem. (Photo by David Ryder/Getty Images)

An Emirati child plays with an airplane model near the venue of the Mazayin Dhafra Camel Festival, on December 20, 2012 near the city of Madinat Zayed, 150 kms west of Abu Dhabi. The festival, which attracts participants from around the Gulf region, includes a camel beauty contest, a display of UAE handcrafts and other activities aimed at promoting the country's folklore. (Photo by Karim Sahib/AFP Photo)

A tourist stands at an edge of the singing sand, the 150-metre-high by three-kilometre-long dune that generates a low-pitched, organ-like rumble in dry weather, in Altyn-Emel national park in Almaty region, Kazakhstan, May 12, 2016. (Photo by Shamil Zhumatov/Reuters)

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)