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.

Award-winning photographer Alex Bernasconi has captured thousands of images – from hiding hippos to wandering zebras – in his travels across Africa. His amazing work features in a new edition of his book Wild Africa. These amazing pictures create a snapshot of the life of some of the planet’s most spectacular animals and natural habitats. Photo: “Wild Africa”. (Photo by Alex Bernasconi)

Plumes of smoke rise from the snow covered volcano Villarrica, in Pucon, Chile on December 7, 2023. (Photo by Cristobal Saavedra Escobar/Reuters)

Beach volleyball athletes from Lithuania and Spain train in Paris on July 25, 2024. (Photo by Louisa Gouliamaki/Reuters)

Residents wearing masks to protect from the coronavirus cross a junction in Beijing on Wednesday, January 20, 2021. (Photo by Ng Han Guan/AP Photo)

A selection of winning images from the Life in Another Light photo contest 2020, from Kolari Vision. Here: Lights and Shadows in the Dolomites, in the landscape infrared category. (Photo by Tomasz Grzyb/Kolari Vision)

Evie and Conor Enright, from Portmarnock pictured on a walk in Howth, Co. Dublin on December 30, 2022. (Photo by Damien Eagers for The Irish Times)

Dancers from Kyiv and Dnipro preparing themselves in the wings for a performance at the Kyiv National Opera House on June 24, 2022. (Photo by Julian Simmonds/The Guardian)