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)

Record snowfall in the Sahara Desert near the town of Ain Sefra in Algeria on January 21, 2017. (Photo by Geoff Robinson/Rex Features/Shutterstock)

This happy couple started married life on top of the world, having exchanged their vows on mount Everest. Dressed in a full suit and wedding dress, James Sissom and Ashley Schmieder spent days scaling the mountain range in order to be photographed in front of such a breathtaking backdrop. Here: James Sissom and Ashley Schmieder exchange vows on Everest. (Photo by Charleton Churchill/Caters News Agency)

Scared of Heights. “Taken from the highest residential building in Asia: the Zenith in Busan. This was taken with official permission (which took me months to get) and safety measures were taken. I had to hang myself over the edge to get this shot. Not for the faint of heart! But when you’re at a height like this, the world below you just seems different. It takes away the fear one would normally have, and gives a sense of peace instead”. (Photo by Albert Dros/NatGeo Cities Travel Photographer of the Year 2017)

“Touring the Koko-en Gardens adjacent to the Himeji castle was an unexpected highlight of our visit”, wrote Jeff Solar, 64, of Silver Spring, Md., about his trip to Japan. “The fall colors were outstanding and the gardens were both amazing and a bargain (just a few Yen added to the cost of the Himeji Castle admission)”. (Photo by Jeff Solar/2017 Washington Post Travel Photo Contest)

A homeless girl asks for alms outside a coffee shop in Mumbai, India, June 24, 2016. (Photo by Danish Siddiqui/Reuters)

A sacrificial camel gets a haircut with patterns at the animal market on the outskirts of Karachi, Pakistan September 22, 2015. Muslims across the world are preparing to celebrate the annual festival of Eid al-Adha or the Feast of the Sacrifice, which marks the end of the annual haj pilgrimage, by slaughtering goats, sheep, cows and camels in commemoration of the Prophet Abraham's readiness to sacrifice his son to show obedience to Allah. Eid al-Adha in India falls on September 25. (Photo by Akhtar Soomro/Reuters)

A reveller dressed as Spider-Man takes part in a presentation at the top of a building during an annual block party known as “Enquanto isso na Sala da Justiça” (Meanwhile, in the justice room), one of the many carnival parties taking place in the neighbourhood of Olinda, Brazil February 7, 2016. (Photo by Ueslei Marcelino/Reuters)