A giant panda cub falls from the stage while 23 giant pandas born in 2016 seen on a display at the Chengdu Research Base of Giant Panda Breeding in Chengdu, Sichuan province, China, September 29, 2016. (Photo by Rex Features)

If we were to burn NH4Cr2O7 with HgSCN in the Dark Ages in Europe and show it to anyone, it is us who would be burning next on a fiery cross of Inquisition. And it’s no wonder, since this experiment produces a truly marvelous result. At first, as you ignite the mixture of NH4Cr2O7 and HgSCN, all you can see is that it is slowly burning with a reddish flame. After a while, however, a crater is formed in the middle of the burning pile, and then, suddenly, tentacle-like appendages start sprouting from the burning mixture. And you can almost hear the scream of the mad occultist – “Come forth, Kraken! Come forth!” But of course, this is simply a chemical reaction that is called the "Pharoah's Serpent". It was also often sold in firework stores until people realized that it was toxic.

This 1931 Stutz DV-32 convertible sedan has 66,000 miles on its odometer and its original leather luggage awaits its first complete restoration Tuesday, March 5, 2013 at L'Cars Automotive Specialties in Cameron, Wis. The company which does high-end restoration and customization work classic cars that have won awards at the world-renowned Pebble Beach Concours d'Elegance. Winning cars include a 57c Bugatti, Rolls Royce PIII V12, V12 Aero coupe, T44 Bugatti, T55 Bugatti, T38A Bugatti, Mercedes Benz 290 Roadster, Rolls Royce Silver Ghost, T57 Bugatti, 1929 Duesenberg J, Mercedes Benz 540K cabriolet, Talbot Teardrop and a 1931 V16 Cadillac convertible. (Photo by Mark Hoffman)

Beautiful, strange and occasionally alarming pictures from the shortlist for this year’s Wellcome image awards – which celebrate the very best in science photography and imaging – from an x-ray of a bat to a micrograph of a kidney stone. The exhibition opens on 12 March at three science centres and the Museum of Science and Industry in Manchester. Photo: Scanning electron micrograph (SEM) of an Arabidopsis thaliana flower, also commonly known as thale cress. Some of the anthers are open, revealing pollen grains ready for dispersal. Arabidopsis was the first plant to have its entire genome sequenced and is widely used as a model organism in molecular and plant biology. Horizontal width of image is 1200 microns. Magnification 100x. (Photo by Stefan Eberhard/Wellcome Images)

The National Geographic Photo Ark is a travelling exhibition of photographer Joel Sartore’s quest to create a photo archive of biodiversity around the world. So far, Sartore has captured studio portraits of more than 6,000 species – a number that he hopes to double. On 1 July, the ark will open at Melbourne zoo – the first time it has been exhibited in the southern hemisphere. More than 50 portraits will be on display, including many of Australian endangered animals being protected by programs at the zoo itself. These captions have been edited from text supplied by Melbourne zoo. Here: Barking owl. (Photo by Joel Sartore/National Geographic Photo Ark/The Guardian)

A bar girl shows off her sexual desires along the Walking Street where bars and sеx scenes are a commonplace July 31, 2016 in Pattaya, Thailand. Thailand's first female minister of tourism would like the sеx trade that is a huge business in the country to be banned. Tourists flock to Thailand for many sights including beautiful beaches but also for sеx tourism. Cities like Bangkok and Pattaya are well known as hubs of the Southeast Asian sеx trade, despite the fact that prostitution has been illegal in Thailand since 1960. (Photo by Paula Bronstein/Getty Images)

A patient solves a rubik's cube at a temporary hospital converted from “Wuhan Livingroom” in central China's Hubei Province on February 10, 2020. In face of the outbreak of the novel coronavirus pneumonia epidemic, Wuhan authorities have transformed public venues such as exhibition centers and gymnasiums into temporary hospitals. The hospitals have a large capacity of treating patients with mild symptoms and play an important role in isolating the source of infection and cutting off the routes of infection during epidemic prevention. The first batch of patients was hospitalized on Feb. 5. (Photo by Chine Nouvelle/SIPA Press/Rex Features/Shutterstock)

Fighting Infections (single image) | Fighting Pandemic by Sudipto Das. “It’s exhausting. A tram conductor in Kolkata, India, wears protective clothing from head to toe even in the heat of a summer afternoon. This was when restrictions were easing after India’s first Covid-19 lockdown – public transport was running, but staff were advised to suit up like this. We’ve all grown used to saluting the efforts of healthcare workers, but plenty of other people in public-facing jobs have performed gruelling duties too to keep people safe”. (Photo by Sudipto Das/Wellcome Photography Prize 2021)