An aerial view of open pits of CODELCO's Andina (L) and Anglo American's Los Bronces copper mines with Olivares glaciers in the background (top L) at Los Andes Mountain range, near Santiago city, November 17, 2014. The rock glaciers of the Chilean central zone, a huge source of water for the basins of the capital, are said to be threatened by the environmental impacts of hydroelectric and mining projects, according to environmental activists Greenpeace. (Photo by Ivan Alvarado/Reuters)

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.

The newest Victoria's Secret “Angels” models pose for photographers in New York's Times Square during the launch of the new “Body by Victoria” campaign July 28, 2015. From L-R front row are Elsa Hosk, Martha Hunt, Sara Sampaio, Jasmine Tookes and Stella Maxwell. From L-R back row are Kate Grigorieva, Taylor Hill, Rommee Strijd, Jac Jagaciak and Lais Ribeiro. (Photo by Mike Segar/Reuters)

(L-R) Alesha Dixon and Amanda Holden attend the Britain's Got Talent 2020 photocall at London Palladium on January 19, 2020 in London, England. (Photo by Doug Peters/EMPICS)

(L-R) Sofía Vergara and Heidi Klum attend Netflix's Primetime Emmy afterparty at Hilex on September 15, 2024 in Los Angeles, California. (Photo by Roger Kisby/Getty Images for Netflix)

Masooma Alizada (L) and Frozan Rasooli (R), members of Afghanistan's Women's National Cycling Team prepare a bicycle before training on the outskirts of Kabul February 20, 2015. Afghanistan's Women's National Cycling Team has been breaking new ground for women's sports and pushing the boundaries of what is – and is not – acceptable for young women in the conservative Muslim country. (Photo by Mohammad Ismail/Reuters)

Greece's Apostolos Angelis (L) and Austria's Felix Leitner compete during the men's 20 km individual event of the IBU Biathlon World Championships in Nove Mesto, Czech Republic on February 14, 2024. (Photo by Joe Klamar/AFP Photo)

Kenya's Reynold Cheruiyot (centre L) and Britain's athlete Jake Wightman fall after crossing the finish line in the men's 1500m final during the World Athletics Championships in Tokyo on September 17, 2025. (Photo by Jewel Samad/AFP Photo)